Although polio has largely receded from public health concerns in the U.S., where it was eliminated more than four decades ago, strains of the virus that causes the disease still circulate in parts of Europe, Asia and Africa. At home, measles outbreaks have recently been reported in Pennsylvania, Virginia and Utah, pushing the total number of cases in the U.S. during 2026 to more than 2,220—already more than last year’s count, according to the Centers for Disease Control and Prevention.

“More than anything, it’s a good reminder that staying up to date on vaccinations is critical to staying safe and healthy while traveling,” said Michael Ben-Aderet, MD, associate director of Hospital Epidemiology at Cedars-Sinai.

The Cedars-Sinai Newsroom spoke with Ben-Aderet about what travelers should know about polio and measles and how to stay safe this summer.

Where does polio still exist?

Polio is caused by a highly contagious virus that has essentially been eliminated from most of the world through vaccination. Wild strains still persist in a handful of countries, including Afghanistan and Pakistan, which means the vast majority of international travelers are at relatively low risk, particularly if they’ve been vaccinated. In recent years, roughly 30 countries in Africa, Europe and Asia, including the U.K. and Germany, have shown signs of the virus circulating. However, those signs are not necessarily tied to outbreaks. For example, public health officials in the U.K. have detected the virus in wastewater tests, which likely points to some degree of asymptomatic polio.

How does polio spread?

The poliovirus typically spreads when an infected person doesn’t wash their hands after using the restroom and contaminates water, food or other surfaces that others touch. It usually causes a mild illness that most people recover from quickly. What makes polio historically frightening is that a small percentage of infections can progress to paralysis, typically affecting the legs and feet, when the virus invades the nervous system. That’s why vaccination is so important. It has essentially eliminated that fear in populations where immunization rates are high.

How big of a threat is polio to international travelers?

Almost everyone in the U.S. received the polio vaccination series as a child. For vaccinated travelers, the risk is minimal. For older adults concerned that their immunity may have waned over the years, a booster is worth considering before visiting regions where polio transmission remains a possibility. The polio vaccine has minimal side effects, so there is little harm in getting the vaccine. You won’t receive the full benefit of immunity until four weeks after vaccination, but you’ll start receiving some protection immediately.

Where is measles a concern?

Measles is, in many ways, a more immediate risk to summer travelers, especially in crowded or enclosed spaces. It’s far more contagious, spreading through airborne particles from an infected person’s cough or sneeze, and it can stay in the air for up to two hours after that person leaves.

Recent clusters have emerged in parts of California, Texas and Oklahoma, and the largest outbreaks have been reported in India, Bangladesh, Yemen, Mexico and Pakistan. Measles outbreaks are happening in multiple countries throughout the world. You could try to avoid known measles outbreaks as you travel, but the chance of encountering someone with measles has risen as fewer people get vaccinated, and you don’t know when you’ll be exposed.

How protected are those who have been vaccinated?

Most fully vaccinated individuals are well protected for life. Adults who are uncertain whether they ever received the two doses of the MMR vaccine, which protects against measles, mumps and rubella, should consider getting at least one dose. Adults at high risk should consider two doses at least 28 days apart. Children are recommended to receive two doses: one at 12 to 15 months and one at 4 to 6 years old. Babies 6 to11 months old should get one dose before they travel and two more doses after their first birthday.

It’s always a good idea to check your vaccination records and to consult your primary care provider or a travel medicine clinic four to six weeks before traveling abroad.

Read more from Cedars-Sinai Stories and Insights: 8 Expert Tips to Avoid Getting Sick When You Travel

experts at Cedars-Sinai are urging residents to take precautions to reduce their risk of infection.

“If you have pets that spend time outdoors, it’s important to take steps to prevent fleas, such as using flea control products,” said Jonathan Grein, MD, director of Hospital Epidemiology and associate professor in the Department of Medicine at Cedars-Sinai. “Typhus is not usually life-threatening, but if it’s untreated, it can result in severe illness.”

Flea-borne typhus, also known as murine typhus, is caused by the bacterium Rickettsia typhi and is transmitted to humans by infected fleas.

According to the L.A. County Department of Public Health, a record 220 cases were reported in 2025—continuing a steady upward trend observed since 2010. At Cedars-Sinai, several patients required hospitalization for flea-borne typhus last year.

“While cases tend to peak in late summer and early fall, expanding urban wildlife habitats and warmer weather are likely contributing to increased transmission year-round, so we want people to be aware,” Grein said.  

The Cedars-Sinai Newsroom spoke with Grein about how flea-borne typhus spreads, its symptoms, treatment and ways to prevent infection.

How do people get flea-borne typhus?

Flea-borne typhus primarily circulates among rats, opossums and stray cats. Fleas that feed on these animals can become infected and then transmit the bacteria to humans through flea bites and flea feces—which enter the body through small breaks in the skin or when rubbed into the eyes.

Pets that spend time outdoors may carry infected fleas into the home, increasing the risk of human exposure. Because many fleas can feed on a single infected animal, the disease can spread and grow quickly within animal and flea populations, making outbreaks likelier to occur among humans.

Is flea-borne typhus contagious?

No. The disease is not spread from person to person; transmission occurs only through infected fleas.

What are the symptoms?

Symptoms are often flu-like and may include fever, headache and muscle aches. Sometimes people will develop a rash on the trunk or back of the body about one to two weeks after symptoms begin. While many cases resolve on their own within about a week, treatment is recommended because some people can develop complications affecting the brain and other organs.

How serious is typhus?

Flea-borne typhus is generally not life-threatening and is typically easy to treat. However, people who are pregnant or have a compromised immune system face a higher risk of severe illness.

Is typhus the same as typhoid?

Typhus is sometimes confused with typhoid fever. While the two have similar names and overlapping symptoms, they are caused by very different pathogens and are not related.

When should someone see a doctor?

Anyone who may have been exposed to fleas and develops persistent fever, severe headache and muscle aches within one to two weeks should seek medical care. A simple blood test is used to diagnose typhus, and early treatment helps prevent complications.

How is it treated?

Treatment typically involves the antibiotic doxycycline for about a week. Most patients respond quickly, with symptoms resolving soon after treatment begins.

How can people prevent flea-borne typhus?

Prevention centers on minimizing exposure to fleas. Keep pets on year-round flea control, avoid contact with wild or stray animals, and keep them away from areas where pets live or eat. Securing trash bins and controlling rodent populations around the home also can help reduce the spread of fleas between animals, and ultimately, to humans.

Read more from Cedars-Sinai Stories and Insights: Stay Healthy as Beach Weather Beckons

“It seems to be a more aggressive strain, and it seems to be a tougher problem,” Sam Torbati, MD, co-chair and medical director of the Cedars-Sinai Emergency Department, said of this year’s flu. “Last year, I don't recall this many patients becoming this ill.”  

Torbati cautioned that it's still very early in Los Angeles’ 2026 flu season, particularly because in the U.S., the flu tends to start along the East Coast and spread westward.  

“It may get much worse,” he said.

The Cedars-Sinai Newsroom spoke with Torbati to learn why patients are getting so sick, how to treat the flu and how to avoid a serious illness.

Who needs emergency care for the flu?

We're seeing a lot of older patients who live by themselves, and if somebody is not keeping an eye on them and they become sick, then no one is taking care of them. They could be lying in bed for two days getting very dehydrated and getting into trouble.

There are also many patients with chronic diseases who develop the flu, and two or three days later they're wiped out. When they come to the hospital, sometimes they’re dehydrated, sometimes they have a bacterial infection and sometimes it's just the flu itself.

The flu, in and of itself, can cause significant problems for patients. It can make them very sick, can make them very much out of it to the point that they can't stand, become dehydrated, and hospitalization becomes necessary to get them back on their feet.

How bad is flu season so far this year?

Around the second week of December, we started seeing a lot of influenza patients coming to the Emergency Department. That spike in flu activity was similarly seen throughout the county. We're seeing patients—the very young, the very old—everybody that gets affected by flu.

We did anticipate, based on some of the predictions from the southern hemisphere, that we were going to see a moderately severe flu season.

What are the most common flu symptoms right now?

In the early phase, we typically see fever, body ache, bone pain, runny nose, cough. The fever usually lasts anywhere from two to five days. Fever tends to stop, and then we end up having a lot of the lingering symptoms. Some patients have coughs that linger for a while. Some can have congestion that can linger for a while. But the average is a good seven to 10 days. So people should expect if they get sick, that it may take that long until they're back to normal, to the point that they feel 100%.

What is the best way to treat the flu?

If you're healthy and younger and you have a viral infection with flu-like symptoms, you basically need to take care of yourself. If you're coughing a lot, take cough medication. If you have a fever, take Tylenol or Motrin. Rest, isolate, drink a lot of fluids so you don't get dehydrated.

For patients who have shortness of breath, asthma or respiratory issues—or for older patients who are developing more severe symptoms—a doctor's visit may become important primarily to make sure that there isn't any complication.

For patients who have underlying medical illnesses—heart failure, COPD (chronic obstructive pulmonary disease), severe asthma, and transplant patients—the sicker and more complicated their medical history is, and the sicker they feel, the more likely it is that a hospital would be helpful, and coming into the ER would be helpful. For some patients, we will prescribe an antiviral called Tamiflu to reduce the risk of a more serious illness if the medication can be started early enough.

What is the best way to avoid a serious flu illness?

It's still not too late to get a vaccine. And although the vaccines are not perfect—they don't completely prevent flu—there is ample evidence to show that they can reduce the severity of what flu does.

Cedars-Sinai Stories and Insights: When to Go to the ER for the Flu

of the highly infectious virus hepatitis A, most adults might not be doing the one, simple thing that can help keep them safe from the virus—washing their hands.

“Many adults do not routinely wash their hands after visiting public places where they come in contact with a wide variety of germs from hundreds, if not thousands, of strangers, or even after using the bathroom,” said infectious disease specialist Soniya Gandhi, MD, MPH, associate chief medical officer and senior vice president of Medical Affairs at Cedars-Sinai Medical Center.

In fact, almost half of adults in the U.S. (48%) do not to wash their hands after visiting a grocery store, restaurant or even a hospital, according to a recent survey from the National Foundation for Infectious Diseases. Estimated rates of hand-washing worldwide after using the toilet are even lower—only 19%, according to the Centers for Disease Control and Prevention.

In addition to getting vaccinated—the best way to prevent hepatitis A, according to physicians—thoroughly washing hands with soap and water before eating or preparing food and after using the bathroom is a key way people can protect themselves from the virus. The Cedars-Sinai Newsroom spoke with Gandhi about how hepatitis A spreads and why good hand hygiene is a critical tool for avoiding the virus and a host of other infectious diseases.

How is hepatitis A transmitted?

Hepatitis occurs when the liver becomes inflamed, and it’s most often caused by one of three viruses: hepatitis A, B or C. Each of these viruses spreads in different ways. Hepatitis A is present in the stool and blood of infected individuals and typically spreads through person-to-person contact or by eating or drinking contaminated food or drink. Food can become contaminated with the virus at any point before it’s eaten—when it’s growing, harvested, prepared or served.  

Why is hepatitis A so infectious?

An infected person can spread the virus—even before they feel sick—by not washing their hands after using the toilet and then touching food that another person later eats. Exposure to even a small amount of the virus can cause an infection, and the virus can survive on surfaces for up to a few months. Not all infected individuals experience symptoms, though adults are more likely to have symptoms than children, and symptoms can take anywhere from two to seven weeks to develop.

What are the signs and symptoms of a hepatitis A infection?

Because the liver processes nutrients, filters the blood and fights infections, symptoms of an infection will be related to the organ struggling to perform those functions. Signs of a hepatitis A illness can include dark urine, pale stools and jaundice—a yellowing of the skin and whites of the eyes—as well as common flu-like symptoms: fever, fatigue, nausea, vomiting and diarrhea. Infections are usually mild, lasting a few weeks to several months. But symptoms sometimes can last up to six months. In rare cases, hepatitis A can cause liver failure and even death.

How can you avoid hepatitis A?

Get vaccinated against the virus and practice good hand hygiene. We all learned about hand-washing and the use of hand sanitizer as a tool for stopping the spread of infectious diseases during the COVID-19 pandemic. But it’s astonishing how many people don’t wash their hands! And make sure you do it thoroughly. If you’re using soap and water, scrub your hands and work up a lather to create friction, which will help eliminate viral particles from your skin. Scrub for at least 20 seconds and dry hands completely because wet hands can more easily transmit germs. If water and soap isn’t available, use a hand sanitizer with at least 60% alcohol concentration. Apply enough to completely cover your hands and rub them together until they’re dry.

What is causing the current outbreak in Los Angeles?

The Los Angeles County Public Health Department reported a spike in hepatitis A infections and high levels of virus in local wastewater, which they monitor for viral pathogens. Although hepatitis A normally spreads among unhoused individuals who don’t have regular access to toilets or hand-washing, and among travelers returning from parts of the world with poor sanitation, this outbreak in Los Angeles is different. It is widespread in the community, and it’s not clear why.

How long does the vaccine for hepatitis A last?

Everyone is encouraged to get the hepatitis A vaccine as a child. It’s a two-dose series starting at 12 through 23 months for the first dose and 2 through 4 years for the second dose. The vaccine has been shown to last up to 20 years. If you’re uncertain whether you’ve been immunized or whether you still have immunity, check your health records or ask your healthcare provider to check your antibody levels.

What is the treatment for a hepatitis A infection?

There is no known treatment for hepatitis A. With supportive care—rest, eating healthy, getting plenty of fluids—the virus usually clears on its own in weeks to months.

Read more on the Cedars-Sinai Blog: Do You Need a Measles Booster? 

The Cedars-Sinai Newsroom spoke to two infectious disease specialists—Jonathan Grein, MD, director of Hospital Epidemiology, and Priya Soni, MD, a pediatric infectious disease specialist at Cedars-Sinai Guerin Children’s—to get the facts about how to protect yourself and your family.

Why is measles so dangerous?

Priya Soni, MD: Many people think that measles is just a rash, but it can be life threatening. One in 5 children who develop measles end up in the hospital. One in 20 children develop pneumonia, and this is the leading cause of measles-related deaths. In addition, 1 in 1,000 children can develop a rare complication of brain swelling—encephalitis—that can cause permanent brain damage.

How does measles spread?

Jonathan Grein, MD: Measles is one of the most infectious diseases that we know of, and it's spread very easily through the air, particularly for people who are not immune or have not received the vaccine. It's so infectious that you don't even need to be in the same room at the same time with someone who has measles to potentially get infected.

What are the telltale signs of measles?

Grein: The symptoms of measles can begin like any other viral illness. You may feel feverish, have muscle aches, headaches, very nonspecific symptoms. Patients may then go on to develop cough, runny nose, sometimes redness of the eyes. That all precedes the classic rash that you may be familiar with that typically starts on the face and spreads throughout the body. I think it’s important to know that it is possible to be infectious several days before that rash begins, which is one of the real challenges with trying to control measles from being spread person to person.

What should you do if you think your child has measles?

Soni: If you think your child has measles, the first thing to do is call your pediatrician, but do not go directly to their offices or the Emergency Department without speaking to someone on the phone first. The virus is extremely contagious, so you want to call ahead to let the healthcare providers know what’s going on. Showing up without calling ahead can cause other children in the waiting room to be infected. In addition, you should immediately isolate your child from other children, especially infants who are less than a year of age, as they may not have protection from the virus. You should also isolate your child from any immunocompromised family members.

How is measles treated?

Grein: The treatment for measles is solely supportive. There is no specific measles treatment, but you want to try to control the fever and make sure the patient is hydrated and resting in isolation.

How do we protect against measles?

Soni: Vaccination is the best protection against measles. The MMR vaccine, which is inclusive of measles, mumps and rubella, is 97% effective after two doses. It's one of the most effective vaccines that we have. And it protects children in outbreak situations and other vulnerable community members as well.

Typically, the first dose of the measles vaccine is given at 12-15 months of age. The second dose is given around 4-6 years of age.

If your child is 6-12 months old, they can receive an early dose of the measles vaccine if they're in a high-risk situation such as an outbreak or if they’ve been exposed to the virus. This additional dose that's given earlier than the recommended schedule does not count toward their two-dose series.

Do adults need to get vaccinated against measles?

Grein: Most adults will not need an additional booster dose if they were previously vaccinated. There is a small number of adults who may have received a different version of the measles vaccine between 1963 and 1967. This vaccine was later found to be less effective, and it doesn't provide as long-lasting immunity as the current vaccine. So if you did receive that vaccine, it is recommended that you receive a booster dose with the current MMR vaccine to achieve appropriate immunity.

Read more on the Cedars-Sinai Blog: Why Some Vaccines Last A Lifetime and Others Don't 

What type of flu activity are we seeing in California this year and what are the symptoms?

As of early January, flu activity in California has been increasing and is comparable to levels observed at this time last year. Influenza (flu) typically presents with sudden onset of high-grade fever, accompanied by body aches, chills, headache, nasal congestion, runny nose and occasionally sore throat or fatigue.

When should you see a doctor?

The course of the flu can vary from person to person, but if you're experiencing prolonged fevers lasting three to five days, worsening cough or shortness of breath, signs of dehydration, or if you have exacerbation of underlying respiratory conditions such as asthma, it may be a good idea to check in with your primary care provider. Additionally, if you develop a new fever after initially recovering from the flu, be aware of the possibility of a secondary bacterial infection, such as a pneumonia, which would require medical attention.

Is it too late to get the flu vaccine?

While getting the flu shot earlier in the season is ideal, vaccination at any point during the flu season can still provide significant protection. The flu vaccine reduces the severity of illness and lowers the risk of complications, especially for high-risk individuals such as young children, pregnant women, the elderly and those with chronic medical conditions.

Each year, the flu vaccine is designed to target the most likely circulating strains. Although the vaccine may not be a perfect match for all strains, it provides partial immunity, which is highly beneficial in preventing severe illness.

What is norovirus and how is it affecting Californians?

Norovirus, often referred to as the “stomach flu,” is a highly contagious virus that causes gastroenteritis. We see symptoms including nausea, vomiting, diarrhea, abdominal cramping and occasionally low-grade fever. Norovirus is one of the leading causes of foodborne illness.

What can people do to stay healthy during virus season?

The advice is always the same. We need to be really mindful of our hand washing and being careful among high-risk individuals. Wearing a mask is of utmost importance because of the fires but also to prevent the spread of respiratory infections in this critical time period during the winter. Additionally, remember to listen to your body and stay home if you’re unwell.

Read more on the Cedars-Sinai Blog: Ask a Doc | What’s Walking Pneumonia?

Officials from the Los Angeles County Department of Public Health reported that several cats tested positive for the bird flu, also called H5N1, after drinking raw milk. Shortly after, the officials reported the first confirmed local case of the illness in a human.

But how much of a threat does the bird flu actually pose to humans?

“This is not yet a threat to everyday people who are not in close contact with affected animals, such as dairy cattle, poultry and wild birds, and we have not seen any human-to-human transmission of the virus,” said Jonathan Grein, MD, director of Hospital Epidemiology at Cedars-Sinai and head of the medical center’s Special Pathogens Response Team, which can test for bird flu and treat the most severe cases.

Though most human cases of H5N1 in the U.S. have been mild since the virus first appeared in 1997, Grein cautioned that the bird flu can be severe and is still evolving.

“We’re concerned that this virus now spreads more readily across mammals—cattle in particular—and as this virus mutates and adapts, it has the potential to spread even more easily,” he said. “We must remain vigilant.”

The Cedars-Sinai Newsroom asked Grein what everyone should know about bird flu, including how to treat it and how to avoid getting sick.

How is bird flu different from seasonal flu?

They’re both from the same family of influenza viruses, but H5N1 binds to different cell receptors. They both cause similar symptoms—fever, sore throat, cough, muscle aches—but conjunctivitis appears to be more common with H5N1 patients who have had close contact with dairy cattle. Both viruses can cause mild illness or more severe forms like pneumonia, but these viruses behave differently. The flu generally follows more established seasonal patterns, whereas H5N1 is more unpredictable. We largely use the same antiviral—Tamiflu—to treat H5N1 as we do to treat seasonal influenza.

How can I know which type of flu I have?

There is no way to determine which virus you’ve contracted unless you get tested. As seasonal flu activity picks up, it will be really important to understand which virus you have. From a public health perspective, we need to understand what’s happening in the community. On a personal level, you’ll want to keep those around you safe, especially if you’ve contracted something beyond the typical seasonal flu.

Will my flu shot also protect me from H5N1?

The flu shot is our most powerful tool to protect yourself and those around you from seasonal influenza. But it likely does not confer protection against bird flu. Vaccines have been developed for H5N1, but they’re not widely available at this time, although some have been stored in a strategic national stockpile to be deployed in an emergency. Drugmakers are developing additional vaccines, and their development process would likely pick up if we began seeing H5N1 spread between humans.

How can I avoid bird flu?

Nearly all cases in humans have been in people who had close contact with dairy cattle, poultry or wild birds. Individuals who must be in contact with these animals should avoid cattle and birds if they appear sick. Also avoid drinking raw milk, which the virus can easily infect.

Read more from the Cedars-Sinai Blog: Flu and RSV—How to Protect Yourself Now

“It’s not just sniffles or cold-like symptoms. It can turn into pneumonia or an even more severe illness for older adults that can lead to hospitalization and, unfortunately, sometimes their demise,” said Leslie Ramirez, MD, a physician with Cedars-Sinai’s Senior Advantage program, which specializes in caring for medically complex Medicare Advantage patients 65 and older.

Because the body’s immune system weakens with age, Ramirez said, viruses like influenza can cause more serious illness in older adults. Once hospitalized, they’re at even higher risk for developing bedsores and skin infections from lack of movement. And unlike younger people whose condition rapidly improves once an illness passes, it can take weeks for older adults to regain their strength.

“If they’ve been in the hospital for a while, when they return home, they can struggle getting in and out of bed, getting to the bathroom or sitting down and standing up,” Ramirez said. “It complicates their care and increases the burden on the family members trying to help them.”

The Cedars-Sinai Newsroom talked with Ramirez about the most effective ways to help older adults avoid a hospital stay altogether.

What can cause an older adult with the flu to need hospital care?

The flu can trigger a huge inflammatory response in the lungs of older adults who may not be able to continue breathing on their own. They might need supplemental oxygen and fluids because we tend to eat and drink less when we’re ill. Dehydration can be very harmful in older patients, causing their blood pressure to drop, as well as respiratory distress.

Older adults also are more likely to have multiple chronic health issues—heart, lung and kidney conditions—and an influenza infection can make all of those worse.

If an older adult gets the flu, how can they avoid a severe illness?

They should contact their provider as soon as they experience flu-like symptoms—fever, chills, body aches, maybe a sore throat or diarrhea—or get tested for the flu at a nearby urgent care. With a confirmed diagnosis, patients might be eligible for Tamiflu, an antiviral treatment that can help shorten the length of illness and decrease severity. But the medication must be started within five days of symptom onset.

It's also important to rest and drink plenty of water. Chicken noodle soup or broth also can help with hydration. Acetaminophen can help reduce a fever, ibuprofen can ease body aches and over-the-counter cough suppressants can help ease a cough. But always check with a provider before taking a new drug to ensure it won’t interact with your current medications or chronic conditions.

Do you have any advice for caregivers or loved ones of older adults?

It’s important to identify flu symptoms early—a fever above 100.4 degrees, chills, fatigue, body aches, an itchy throat. If you notice that an older loved one with the flu is starting to become more lethargic, very weak or confused—they don’t know where they are or who they are, and they’re usually very aware of their surroundings—those are big flags that the severity of their illness is increasing. Take them to the emergency department or call their provider immediately.

If they start complaining that they haven’t gone to the restroom as much as they normally do, that could be a sign they’re not drinking enough, or their kidneys aren’t functioning well. If their cough worsens and they’re having difficulty breathing or they’re short of breath or they can’t walk to the bathroom—those are all red flags.

How can older adults avoid the flu?

Wash your hands, especially if you’re going to be eating or you’ve been in an environment that might not be clean. You might want to avoid crowded places like giant sporting events during flu season. I’m not advocating that people skip important life events like a wedding or gathering with family, but take precautions, such as masking or keeping your distance. Some people still choose not to shake hands.

And, of course, get the flu shot. The flu vaccine is available at local pharmacies and in our clinic at Cedars-Sinai. For those 65 and older, there is a high-dose flu shot because their immune system isn’t as reactive as it used to be, and they need a stronger dose to mount a successful immune response. Younger family members also should consider getting vaccinated to reduce their risk of contracting influenza and passing it on to their older relatives. But remember, it takes two weeks to become fully protected. Keep that in mind if you want to time your flu shot ahead of Thanksgiving, the holidays or major travel.

Read more on the Cedars-Sinai Blog: Care Coordination for the Sandwich Generation

That’s because global warming causes temperatures to rise which, in turn, expands the reach of insects carrying infectious diseases. Species of mosquitoes that thrive in warmer environments are finding newly hospitable homes in places where the climate is warming and the summer heat lingers longer. As a result, physicians in once mild parts of the U.S. are seeing increasing cases of mosquito-borne diseases, such as Zika virus, West Nile virus and now dengue fever. 

“Warmer weather means warmer pools of standing water, a friendlier environment for breeding mosquitos, especially without very cold winters to kill off the eggs and larvae,” said Kimberly Shriner, MD, medical director of Infection Prevention and Control at Huntington Health, an affiliate of Cedars-Sinai. “There is no question that we’re seeing more Aedes mosquitos—the species that carries dengue—because of hotter temperatures.”

Another cause: People are traveling more widely and frequently, said Michael Ben-Aderet, MD, associate medical director of Hospital Epidemiology at Cedars-Sinai. He explained that this increases the odds that a traveler returns home with a mosquito-borne infectious disease, gets bit by one of the many Aedes mosquitos now thriving in Southern California, and that bug carries that disease to someone else.

“Dengue is well known in tropical places like South America, Central America and Puerto Rico,” Ben-Aderet said. “We’ve always had dengue cases in Los Angeles linked to travel, but now we’re encountering patients who haven’t traveled at all—they’ve never left Los Angeles. These individuals were bitten by mosquitoes locally. This suggests that there are likely more mosquitoes carrying dengue that we haven’t detected yet, partly because we’re not testing frequently enough and many people with dengue don’t become very ill.”

He added that Southern California is a perfect environment for dengue transmission. “We have mosquitos, a big population and people are traveling more than ever before,” he said.

Breakbone Fever

The Aedes mosquitos that can spread dengue, as well as Zika virus, started showing up in Southern California about a dozen years ago. While most people are familiar with the ankle-biting tendency of these mosquitos, they’re likely less aware of dengue and the disease’s symptoms.

Dengue can cause a wide range of symptoms from none at all to very severe, Ben-Aderet said. It starts with a high fever and severe muscle pain, giving it the nickname “breakbone fever.”  Dengue often appears with a diffuse red rash that blanches, turning white or the color of one’s skin after pressing on the rash and releasing pressure. Patients can also experience gastrointestinal symptoms like nausea.

The second time someone gets dengue, it can be much worse, said Shriner, who has treated patients with disease during annual medical mission trips to Tanzania with a nonprofit that provides clinical care and medical education. Dengue is a hemorrhagic fever, like the Ebola virus, that can cause bleeding—in this case, bruises bloom under the skin from “leaky” blood vessels.

For mild cases, treatment is supportive care: fluids, rest and Tylenol. More severe cases might need intensive care in a hospital. Highly specialized vaccines exist, but they’re primarily intended to help children avoid a dangerous second infection in places like the Philippines where the disease is endemic.

Canary in the Coal Mine

For local physicians, the spread of tropical diseases in once milder climates means they must think more broadly when diagnosing a sick patient.

"Whenever I see a patient in today's world, I need to keep a very open mind about what they might have," Ben-Aderet said. He added that the sporadic dengue infections we’ve seen from area mosquitos indicate we don’t yet have a “reservoir,” a sustained source of infections to make dengue endemic to Los Angeles. But it could happen in the not-too-distant future, he said.

Shriner emphasized that she doesn’t want people to panic. “We should be worried more about COVID-19 and the flu,” she said.

Still, she cautioned that smaller, novel outbreaks—like the emergence of dengue in Los Angeles—are “canaries in the coal mine” sending a message that we need to pay attention.  

“We live in an interconnected world with a fragile climate that is changing,” Shriner said. “We want to approach this scientifically, compassionately and with humanity. All of us are at risk for these diseases; all of us need to find solutions together.”

Read more on the Cedars-Sinai Blog: Everything You Need to Know About Bug Bites

Vaccination clinics begin Sept. 9 and are scheduled through November across Los Angeles County.

“Cedars-Sinai is committed to keeping our community as healthy as possible during this upcoming flu season,” said Jonathan Vickburg, LMFT, associate director of Community Health Improvement at Cedars-Sinai. “Influenza is a serious disease, especially for young children and older adults. If you haven’t gotten your vaccination yet, please come see us at one of our clinics.”

Influenza can cause severe illness that can lead to hospitalization and even death. Symptoms include fever, chills, cough, sore throat, fatigue, nausea, diarrhea, runny nose and muscle aches. Flu activity often accelerates in October, making it critical to get vaccinated now. Infectious disease experts  from Cedars-Sinai strongly urge adults, children and infants to get the flu vaccine.

“You think it will never happen to your family, but every year, thousands of people in the U.S. die from flu complications,” said Jonathan Grein, MD, Cedars-Sinai’s director of Hospital Epidemiology and associate professor in the Department of Medicine. “It takes only a couple of seconds to get a shot and protect yourself and everyone in your family who is eligible for the shot, including babies 6 months and older and pregnant women.”

The flu vaccines formulated for the 2024-25 flu season protect against three different flu viruses that are circulating this year. Infectious disease experts recommend that everyone 6 months old and up get vaccinated. All ages are welcome at the community flu shot clinics, and children must be accompanied by a parent or guardian.

Scheduled Clinics:

Monday, Sept. 9
10 a.m.–1 p.m.
Roxbury Park 
471 S. Roxbury Dr. 
Beverly Hills, CA 90212

Sunday, Sept. 15
11 a.m.–2 p.m.
Saint Basil's Church
3611 Wilshire Blvd.
Los Angeles, CA 90005

Thursday, Sept.19
7:30–10 a.m.
Hope on Union – United University Church
2208 S. Union Ave. 
Los Angeles, CA 90007

Sunday, Sept. 29
8–11 a.m.
St. Kevin Catholic Church
4072 Beverly Blvd.
Los Angeles, CA 90004

Tuesday, Oct. 1
10 a.m.–1 p.m.
Plummer Park Community Center
7377 Santa Monica Blvd. 
West Hollywood, CA 90046

Friday, Oct. 4
9 a.m.–noon
Immanuel Presbyterian Church
3300 Wilshire Blvd.
Los Angeles, CA 90010

Sunday, Oct. 6
9 a.m.–noon
Cedars-Sinai Medical Center – Steven Spielberg Parking Lot
8723 Alden Dr.
Los Angeles, CA 90048

Saturday, Oct.19
7 a.m.–noon
Children's Institute Inc. – Otis Booth Campus
2121 W. Temple St.
Los Angeles, CA 90026

Wednesday, Oct. 23
10 a.m.–noon
Watts Labor Community Action Committee (WLCAC)
2528 West Blvd. 
Los Angeles, CA 90016

Saturday, Nov. 2
7 a.m.–noon
Michelle and Barack Obama Recreation Center
5001 Obama Blvd.
Los Angeles, CA 90016

Sunday, Nov. 10
9–11 a.m.
Young Israel of Century City
9317 W. Pico Blvd.
Los Angeles, CA 90035

Tuesday, Nov. 12
Noon–2 p.m.
Fairfax Senior Citizens Center 
7929 Melrose Ave.
Los Angeles, CA 90046

Read more on the Cedars-Sinai Blog: Flu and RSV: How to Protect Yourself Now

Flu shots are available now at Cedars-Sinai medical offices—even as much of the U.S. continues to cope with unusually high levels of COVID-19 infections from that virus’ summer surge.

Though COVID-19 tends to taper off in the autumn—when flu and RSV (respiratory syncytial virus) are beginning to set in—whether the U.S. will have a tough virus season is unpredictable at this point.

“Only one thing is certain,” said Jonathan Grein, MD, director of Hospital Epidemiology at Cedars-Sinai and associate professor in the Department of Medicine. “We will definitely see influenza, COVID-19 and RSV circulating at the same time this winter.”

The most important advice Grein has for surviving this year’s respiratory virus season: Get vaccinated.

“The flu shot is still our most powerful tool to avoid influenza-related hospitalizations and deaths and keep our community safe,” Grein said. “The flu is linked to tens of thousands of deaths every year in the U.S. in addition to hospitalizations and clinic visits.”

The Cedars-Sinai Newsroom spoke with Grein for more information on vaccines, where to get medical care and other helpful advice for getting through flu season.

If someone gets sick, how can they tell which virus they have, and does it matter?

It can be tricky to tell these three illnesses apart because the flu, COVID-19 and RSV all can share similar symptoms—nasal congestion, headaches, fatigue, muscle aches, sore throat, cough and fever, and shortness of breath in more severe cases. Vomiting and diarrhea also can occur with COVID-19 or the flu. Only loss of taste and smell is more specific to COVID-19, though that occurs less often than it did early in the pandemic.

It’s important to get tested quickly to determine which illness—or illnesses—are causing your symptoms. Depending on which virus you have, you might need to start a particular treatment soon after symptoms appeared. If you’re considered high-risk—an older adult, someone who is immune-compromised or has a chronic health condition—your provider might recommend Paxlovid if you have COVID-19 or Tamiflu if you have the flu. To have the most benefit, Paxlovid should be taken within five days of symptom onset and Tamiflu within 48 hours, so it’s important to act quickly.

Who should get vaccinated against the flu, COVID-19 and RSV?

We strongly encourage adults and children older than 6 months to get the flu and COVID-19 vaccines. Ideally, you would get the flu shot in September or October and the updated COVID-19 vaccine when it becomes available shortly. Remember that it takes a couple of weeks for your immune response to develop after getting a shot.

Cedars-Sinai primary care physicians and pediatricians are now offering flu shots to patients during scheduled visits. Patients who have been treated by a Cedars-Sinai primary care provider in the past 16 months can schedule a vaccination appointment through My CS-Link at locations in Beverly Hills, Marina del Rey, Santa Monica, Los Feliz, Playa Vista and Tarzana.

To make an appointment for a COVID-19 vaccination, visit the My Turn website from the California Department of Public Health.

We also now have an RSV vaccine for older adults, a shot for pregnant people and an immunization for babies. If you or a loved one is in one of these groups, we recommend speaking with your physician to determine if the immunization or the vaccines are appropriate. 

When should someone seek treatment for flu-like symptoms?

Most mild symptoms can be managed at home with supportive care—fluids, Tylenol, rest. A humidifier can help with congestion and a saline nasal rinse can help clear mucus. Little kids might also benefit from a nasal suction device.

If you’re not sure if your symptoms are more serious, a virtual appointment is an easy way to get an expert opinion. Cedars-Sinai Connect offers quick access to Cedars-Sinai providers—available 24/7 for urgent issues—for those in California, including kids aged 3 and older, Spanish-speaking adults and patients new to Cedars-Sinai. Individuals with immediate concerns that are not life threatening—prolonged dizziness, not tolerating food or fluids—should visit urgent care. If symptoms truly are life threatening—difficulty breathing, pain or pressure in the chest or abdomen—go to the nearest emergency department. 

How long is someone contagious after getting sick with a virus?

Every virus is a little different, but in general people start becoming infectious with a respiratory virus shortly before their symptoms start, and then remain infectious for several days afterward when their symptoms are improving. With the flu, you’re infectious a day before symptoms start and until after a fever has resolved and symptoms are improving, as long as five to seven days after getting sick. It’s helpful to think of infectiousness as more of a gradient than an on or off switch. It’s also not unexpected for a cough to linger for many days or weeks after you’ve recovered, but it does not always imply you’re infectious for that period of time.

Is there anything unusual about this year’s flu season?

We should keep a close eye on what happens with the “bird flu,” the avian influenza A(H5N1) virus. Multiple outbreaks in cattle and poultry since the spring have been connected to more than a dozen infections in humans in the U.S. Even if you don’t work on a farm, it’s still relevant information. Families tend to visit farms in the autumn, and raw milk—which is sold in some health food stores—is another potential risk factor.

The good news is that we haven’t seen any human-to-human transmission of H5N1 with these recent cases in the U.S., but public health authorities are watching these outbreaks closely. If you’re someone who has been in close contact with cattle or poultry—even if it’s at a petting zoo or county fair—and you develop flu-like symptoms, alert your physician about your exposure to animals. I’d recommend washing your hands after being in contact with these animals and avoiding raw milk.

Read more on the Cedars-Sinai Blog: Tips to Survive Peak Flu Season from a Cedars-Sinai Expert

“We've seen a bit of a seasonal pattern emerge where we've had an uptick in COVID in the summer and then another one in the winter—usually the winter one being more severe,” said Michael Ben-Aderet, MD, associate medical director of Hospital Epidemiology at Cedars-Sinai.

The western U.S. is riding the biggest wave. Wastewater data for the region shows the virus that causes COVID-19 jumping from moderate to high levels in late June. The area had seen minimal levels circulating as recently as mid-May.

The uptick has largely been driven by the so-called FLiRT variants of COVID-19, such as KP.3 and KP.2, newer strains of the virus that began spreading in the spring. To stay on top of this latest wave, the Cedars-Sinai Newsroom sat down with Ben-Aderet to learn more about the FLiRT variants and why COVID-19 spikes over the summer.

Why are we seeing a COVID-19 spike this summer?

This has been the case for a couple of years. Why that is, I don't think anyone truly understands. A lot of viruses are seasonal in nature. Some viruses are seasonal in summer; some are in winter. COVID-19 seems to be in both. Some of that has to do with the virus itself—the virology, how it spreads. And another aspect of it is human behavior: School being out, people being on vacation, people traveling, people mixing and doing more activities does play a role in that summer surge.

What are the FLiRT variants?

The FLiRT variants is just a technical term for the continued mutation of the Omicron variants of COVID-19. And for the last year or so, pretty much all the variants of COVID-19 that we've seen circulate in the United States have been variants of Omicron.

How are the FLiRT variants different from previous versions of the virus?

So the symptoms that we're seeing in patients that are infected with one of the FLiRT variants are the same symptoms that we've been seeing with COVID-19 all along. There's no sense that there's any increased severity with the FLiRT variants. We're still seeing the relatively mild disease that we've been seeing with COVID-19 over the past year. It's primarily an upper respiratory illness. So think fever, chills, cough, runny nose, stuffiness— similar to a cold, essentially. And sometimes gastrointestinal symptoms.

Are existing COVID-19 tests and treatments still effective with the new variants?

All available testing, both commercial and home testing, will still test against the FLiRT variants. Paxlovid is still widely available and still works very well. So there hasn't been any reduction in activity of Paxlovid, and it’s still recommended for high-risk individuals with COVID-19.

How can we avoid getting COVID-19 at this point?

Masks still work. Make sure to wear a good, well-fitting mask. They’ve been proven to help prevent the spread of COVID-19. If you haven't been vaccinated, vaccines are still available, and it's really best to be up to date on your vaccinations. Avoid being around others who are sick. If you are exposed or if you're sick, stay home if you don’t need to go out.

Read more on the Cedars-Sinai Blog: Long COVID—What to Know

Based on results from new clinical trials, the Centers for Disease Control and Prevention (CDC) recently issued proposed guidelines for using doxycycline to reduce the risk of a chlamydia or syphilis—and possibly gonorrhea—infection among sexually active adults. Experts say new preventive approaches are critical to control the widening STI epidemic, fueled in part by the disruption in healthcare services during the height of the COVID-19 pandemic.

“Even before COVID started, we had seen a significant increase in STDs [sexually transmitted diseases], both internationally and here locally in California,” said Christopher Foltz, MD, an infectious disease specialist at Cedars-Sinai. “Syphilis has been climbing at the highest rate with a significant increase among pregnant women and men who have sex with men.” 

Growing Problem

Syphilis cases among men who have sex with men rose 7% from 2020 to 2021, according to the CDC. Syphilis rates among women jumped 55.3% from 2020 to 2021, and 217.4% from 2017 to 2021, which has led to the birth of more babies with the disease.

People with syphilis often don’t have symptoms, Foltz said, and when they finally visit a doctor, they may have been infected for months—or even years—without knowing it. Undiagnosed long-term infections can lead to permanent complications, including blindness and permanent neurologic damage.

“That's what we're trying to prevent—these kinds of catastrophic long-term complications from undiagnosed STIs,” Foltz said. “If we can prevent infections with a relatively safe and easy-to-take antibiotic, the overall number of new infections will ultimately decrease.”

Old Drug, New Use

Doxycycline has long been a go-to treatment for acne, skin infections, illnesses spread by tics and pneumonia. The drug had been on the radar of physicians treating STIs for years, but previous clinical trials hadn’t shown it would be effective as a preventive therapy. Physicians have become increasingly hesitant to prescribe antibiotics when they’re not needed amid a rise in antibiotic-resistant bugs.

“Bacteria can figure out how to avoid being killed by antibiotics,” explained clinical pharmacist Greg Marks, PharmD, coordinator of the Antimicrobial Stewardship program at Cedars-Sinai Medical Center, which closely tracks the use of antibiotics in the hospital. “In general, the more we use antibiotics, the more concerned we are about resistance.”

But new trial results showed doxycycline could be an effective new tool to limit the spread of syphilis and chlamydia if taken as a single 200-milligram dose within 72 hours after unprotected sex, Marks said. Using doxycycline to prevent gonorrhea showed some promise but yielded mixed results.

Only one dose of the antibiotic is necessary in a three-day period to help avoid these bacterial infections, even if having sex with multiple partners. The strategy, dubbed “Doxy on Demand” or “Doxy-PEP” (post-exposure prophylaxis), is similar to taking the morning-after pill to prevent pregnancy after unprotected sex. But this new treatment isn’t a reason to ditch condoms.

“This by no means is a way to offset the use of condoms,” Foltz cautioned. “We absolutely encourage condom use to prevent against other STDs and HIV [human immunodeficiency virus] as an added barrier of protection for prevention.”

Foltz said the people most likely to benefit from this new strategy are those who have had STDs recently, those taking HIV medications or medications to prevent the spread of HIV, and members of the LGBTQ+ community, which tends to experience higher rates of certain STIs.

Pregnant women should generally avoid the drug, Marks said, as well as people allergic to tetracyclines, a class of antibiotics. He and Foltz encouraged patients to speak with a physician about whether doxycycline might be right for them.

“If you're actively having sex and not using condoms 100% of the time, which is the reality out there, this strategy could be appropriate for you,” Foltz said. “It comes down to each person’s individual risk level, something that you should discuss with your physician.”

Read more on the Cedars-Sinai Blog: Gaining Ground on HIV/AIDS

Their findings, published today in the peer-reviewed journal Cell Reports, could aid future studies looking at the effects of diet and the microbiome, especially the process of fiber metabolism by gut microbes.

The team of investigators—led by Ivan Vujkovic-Cvijin, PhD, assistant professor in the department of Biomedical Sciences and department of Gastroenterology at Cedars-Sinai—are among the first to find that looking for fiber metabolites—molecules that strengthen gut barrier integrity and immune function—in blood samples, versus traditional stool samples, provides a more accurate representation of production of these metabolites by the gut microbiome.  

With this knowledge, investigators also discovered that gut microbial production of these fiber metabolites is related to the prevention of heart disease and death in people with HIV, the virus that causes acquired immunodeficiency syndrome (AIDS).

“This is an important step in the human microbiome field because the high-fiber diet has been shown to protect from a remarkable number of diseases, but the field has struggled to quantify the immediate effects of such diets,” said Vujkovic-Cvijin, corresponding and senior author of the study. “We anticipate our discovery will allow better quantification of microbial fiber metabolism and will lead to a greater understanding of the precise pathways that link fiber metabolites to protection from diseases and early death in people with HIV.”

People with HIV have long been known to experience higher rates of many diseases and premature death, despite being treated with optimal antiretroviral therapy. The medical field also knows, based on past studies from Vujkovic-Cvijin and team, that the gut microbiota of people with HIV is different from that of those who are HIV-negative.

This latest research sheds light on the “why.”

Investigators found that an abundance of microbial enzymes involved in fiber deprivation correlates more strongly with fiber metabolite levels in blood than in stool.

Through this research, the team also found that significantly higher levels of these microbial enzymes were found in people who did not later succumb to heart disease or death, suggesting the importance of this pathway in the health of people with HIV.

“Thanks to this important research, we now understand that a lack of ability of the gut microbiome to digest fiber precedes medical conditions like heart disease, suggesting this function of the microbiome may also contribute to their development,” said David Underhill, PhD, chair of the Department of Biomedical Sciences, who was not involved in the research study.

Underhill said future studies may also gain more information by examining blood levels of fiber metabolites, instead of examining stool samples.

“Blood samples appear to paint a clearer picture of who might best benefit from fiber, and which types,” said Underhill.

Looking ahead, Vujkovic-Cvijin also plans to focus future research efforts on the precise pathways that may link fiber metabolites to protection from disease and early death in people with HIV.

“There are several likely candidates, and we hope to uncover which of these pathways might have the greatest impact on health,” said Vujkovic-Cvijin.

Additional Cedars-Sinai authors include Alice Lo and Jacob Gifford. Other authors include Irini Sereti, Myrthe L. Verburgh, Anders Boyd, Eveline Verheij, Aswin Verhoeven, Ferdinand W.N.M. Wit, Maarten F. Schim van der Loeff, Martin Giera, Neeltje A. Kootstra, and Peter Reiss.  

DOI: 10.1016/j.celrep.2023.113336

Funding: Vujkovic-Cvijin was funded by the Crohn’s & Colitis Foundation Career Development Award. This work was supported in part by The Netherlands Organization for Health Research and Development and AIDS Fonds and by the intramural research program of NIAID/NIH.

Read more from the Cedars-Sinai Blog: Cedars-Sinai Investigators Exploring the Connection Between the Microbiome and Diabetes

“We urge everyone in our community to get vaccinated because it’s so important for everyone’s health,” said Jonathan Vickburg, LMFT, associate director of Community Health Improvement at Cedars-Sinai. “Holding free flu vaccine clinics is the best way to demonstrate our commitment to our community’s health and wellbeing.”

The Oct. 8 clinics are part of a series of more than 40 free, Cedars-Sinai Health System flu vaccination clinics throughout the community. A list of upcoming clinics is below.

Influenza can cause severe illness that can lead to hospitalization and even death. During the 2022-2023 flu season in the U.S., the flu was linked with as many as 650,000 hospitalizations and as many as 58,000 deaths, according to the Centers for Disease Control and Prevention.

Flu activity often accelerates in October, making it critical to get vaccinated now if individuals haven’t already received their shots. Infectious disease experts from Cedars-Sinai and its affiliates strongly urge adults and children 6 months and older to get the flu vaccine.

“The flu shot is the best tool we have to protect ourselves from the flu,” said Kimberly Shriner, MD, medical director of Infection Prevention and Control at Huntington Health. “Make sure everyone in your home is vaccinated against the flu and also up to date on COVID-19 vaccinations as we approach the holiday season when people will be gathering.”

People especially vulnerable to the flu include adults 65 and older, patients with certain chronic medical conditions (asthma, diabetes, heart disease), those who are pregnant and children younger than 5.

“We hope that the public will take advantage of these free flu clinics to protect themselves and others in their community who are vulnerable to the flu,” said Torrance Memorial infectious disease specialist David D. Rand, MD.

The complete list of flu vaccination clinics includes:

• Cedars-Sinai Medical Center–Spielberg Building
  Oct. 8, 9 a.m.–12 p.m.
  8723 Alden Drive, Los Angeles 90048
   
• Huntington Health–Light of Love Mission Church
  Oct. 8, 9:30–11:30 a.m.
  2801 E. Colorado Boulevard, Pasadena 91107
   
• Torrance Memorial–Richard B. Hoffman Health Conference Center
  Oct. 8, 9:30–11:30 a.m.
  3315 Medical Center Drive, Torrance 90505
   
• Huntington Health–Friends In Deed
  Oct. 10, 9–11 a.m.
  444 E. Washington Boulevard, Pasadena 91104
   
• Huntington Health–Jefferson Public Library
  Oct. 10, 10 a.m.–12 p.m.
  1500 E. Villa Street, Pasadena 91106
   
• Huntington Hospital–Cafeteria
  Oct. 11, 11 a.m.–1 p.m.
  100 W. California Boulevard, Pasadena 91105
   
• Huntington Health–South Pasadena Farmer’s Market
  Oct. 12, 4–6 p.m.
  905 Meridian Avenue, South Pasadena 91030
   
• Huntington Health–Living Rock Church
  Oct. 14, 9–11 a.m.
  2181 E. Washington Boulevard, Pasadena 91104
   
• Cedars-Sinai–St. Kevin Catholic Church
  Oct. 15, 8–11 a.m.
  4072 Beverly Boulevard, Los Angeles 90004
   
• Huntington Health–St. Elizabeth Parish School
  Oct. 15, 9–11 a.m.
  1840 N. Lake Avenue, Altadena 91001
   
• Huntington Health–St. Joseph Center (Holy Family Giving Bank)
  Oct. 16, 8–10 a.m.
  1524 Fremont Avenue, Pasadena 91030
   
• Huntington Health–Villa Parke Farmer’s Market
  Oct. 17, 9–11 a.m.
  363 E. Villa Street, Pasadena 91101
   
• Cedars-Sinai–Plummer Park
  Oct. 17, 10 a.m.–1 p.m.
  7377 Santa Monica Boulevard, West Hollywood 90046
   
• Huntington Health–Hastings Branch Public Library
  Oct. 18, 10 a.m.–12 p.m.
  3325 E. Orange Grove Boulevard, Pasadena 91107
   
• Cedars-Sinai–Taste of Soul Event
  Oct. 21, 10 a.m.–7 p.m.
  Crenshaw Boulevard (between Stocker and Obama)
   
• Huntington Health–Community Church (Dream Church)
  Oct. 22, 9–11 a.m.
  1305 E. Colorado Boulevard, Pasadena 91106
   
• Huntington Hospital–Emergency Department
  Oct. 24, 4–6 p.m.
  100 W. California Boulevard, Pasadena 91105 (Fairmount Courtyard Entrance)
   
• Huntington Health–Sacred Heart Church
  Oct. 29, 10 a.m.–12 p.m.
  2835 N. Lincoln Avenue, Altadena 91001
   
• Cedars-Sinai–Young Israel of Century City
  Nov. 5, 9 a.m.–12 p.m.
  9317 W. Pico Boulevard, Los Angeles 90035

Visit Cedars-Sinai’s events page and Huntington Health’s flu page to find a nearby location.

Read more on the Cedars-Sinai Blog: Cold vs. Flu Symptoms

Flu season started early in the Southern Hemisphere, which typically gives experts some clues as to what we’ll experience here in the U.S. To avoid getting caught off guard, it’s important to get the flu shot in September or October, said infectious disease specialist Soniya Gandhi, MD, MPH, associate chief medical officer at Cedars-Sinai.

“Even a typical flu season can be deadly and can cause significant hospitalization,” Gandhi said, pointing to 58,000 deaths in the U.S. and more than half a million hospitalizations—all caused by last year’s flu. “We should do what we can to protect ourselves—and others—with the best tool we have: the flu vaccine.”

Cedars-Sinai primary care physicians and pediatricians are now offering flu shots to patients during regularly scheduled visits. Patients who have been treated by a Cedars-Sinai primary care provider in the past 16 months can schedule a vaccination appointment online through My CS-Link at clinics in Beverly Hills, Marina del Rey, Santa Monica, Los Feliz, Playa Vista and Tarzana.

In addition to the flu, COVID-19 and the respiratory syncytial virus (RSV) could again spike at the same time, triggering a “tripledemic,” Gandhi said. Last year, that same triple punch filled emergency departments across the country and strained children’s hospitals with young patients, who are vulnerable to RSV—a virus that can be serious, if not deadly, for infants and older adults.

But there’s a silver lining this year. In addition to the flu vaccine, new RSV shots are available for babies and adults over 60, and a new COVID-19 booster is coming this fall.

“These new shots and vaccines could really help protect us and our community during the upcoming season,” Gandhi said. “We need to preserve capacity in hospitals for those patients who really need that care.”

Help for Youngest and Oldest

RSV causes mild cold-like symptoms in most people, but it’s the leading cause for hospitalization among infants in the U.S. In babies, the virus can cause mild illness or it can cause dangerous inflammation in a child’s tiny airways.

“There's really no way to predict how your child would do even if they're completely healthy,” said Priya Soni, MD, a pediatric infectious disease specialist at Cedars-Sinai Guerin Children’s. “If they do end up having a horrible course with RSV, they will likely need to be hospitalized for oxygen support, fluids and other supportive measures.”

Most children in the U.S. will be infected with RSV within the first year of their life, and almost all infants will have been exposed to the virus by the time they're 2 years old.

But parents of infants have a new way to protect their children. The U.S. Food and Drug Administration (FDA) recently approved an immunization—a monoclonal antibody treatment called nirsevimab-alip (Beyfortus)—that can be given as a single-dose shot to newborns and infants during their first RSV season. Children up to 19 months old who remain vulnerable to severe disease in their second RSV season also can get the shot.

Soni said she “100%” recommends the immunization because of strong clinical trials that yielded positive results.

The FDA also recently approved a Pfizer RSV vaccine for women who are 32-36 weeks pregnant to protect their infants at birth. The same vaccine also was approved for adults 60 and older, as was another vaccine from pharmaceutical company GSK.

For older adults, the Centers for Disease Control and Prevention (CDC) recommended these new vaccines only for those who are at highest risk of severe RSV, such as patients with asthma, diabetes or heart failure. Although both vaccines are considered safe, a very small number of cases of Guillain-Barre syndrome—a condition in which a person’s immune system attacks their peripheral nerves—were reported after vaccination.

More data is needed to determine whether these episodes may have been unrelated to the vaccine, according to the CDC. But the significant risk RSV poses to some older adults could outweigh the very low risk of developing potential side effects.

Sonja Rosen, MD, section chief of Geriatric Medicine at Cedars-Sinai, said that for now,  she recommends the RSV vaccine for older patients with lung disease, or for those who are otherwise immunosuppressed and therefore at higher risk for severe illness. “Patients should speak with their physician and make an informed decision about whether this shot is right for them,” Rosen said.

New Twist on the COVID-19 Booster

The new COVID-19 booster has been updated to include a sub-variant of Omicron called XBB, which was the predominant strain at the time the shot was approved by the FDA this summer.  The vaccine should provide protection from all the strains circulating in the U.S. right now, Gandhi said.

Thanks to the new booster, antiviral medications like Paxlovid and at-home tests, Gandhi is grateful that “we're in a very different position in 2023.” She encouraged the public to take advantage of the booster when it becomes available this fall, to keep themselves and their loved ones safe, especially when gathering throughout the fall and winter holidays.

“We know immunity wanes after the administration of the booster and that many individuals may not have had a booster for quite some time,” Gandhi said. “I think it will be incredibly important, particularly in those populations that are vulnerable to COVID illness, hospitalization and potentially even death, to ensure that they get the updated booster in a timely fashion.”

She said it’s safe to get the COVID-19 and flu vaccines together. For older adults who determine with their physician that the RSV shot is right for them, they should get that immunization alone and two weeks apart from the other vaccines, if possible, Gandhi said. 

Read more on the Cedars-Sinai Blog: Flu—When to Go to the ER

Only this time, there’s good news: The number of infections hasn’t increased as much as in past summers. Plus, most people with COVID-19 are reporting mild symptoms, and hospitalizations in the U.S. are significantly lower than they were last year at this time.

At the end of July 2022, some 38,000 people nationwide were hospitalized with COVID-19. Late July 2023 saw 7,000 patients hospitalized—just 18% of July 2022 hospitalizations. Although it’s the highest number of COVID-19 hospitalizations since June, it’s also a lower number than any point in previous years during the pandemic.

Infectious disease specialist Jonathan D. Grein, MD, director of Hospital Epidemiology at Cedars-Sinai, said that experts aren’t sure why COVID-19 surges in the summer months, though there are many theories.

“We expect surges in the winter—that’s when we typically see a lot of respiratory viruses circulate,” Grein said. “But we also see respiratory infections in the summer, and COVID-19 is no exception. One reason for this summer’s uptick in cases could be that people’s immunity has waned over the course of the year, but really, it’s just speculation.

“The bottom line is that we should all be mindful that we’re seeing more COVID in our community right now, and we shouldn’t let down our guard.”

Still, today’s COVID-19 reality is much different from the early days of the pandemic, when COVID-19 was the third-leading cause of death in the U.S. between March 2020 and October 2021, according to the National Institutes of Health. Today, most patients with COVID-19 who are hospitalized at Cedars-Sinai Medical Center are hospitalized for unrelated reasons, Grein said, and were incidentally found to have the virus.

“It’s important to keep in mind when looking at hospitalization data that it doesn’t always necessarily reflect severity of illness,” he said. “We have seen some sicker patients requiring higher levels of care—especially among those who were already at risk for severe illness—but the good news is that it’s been relatively infrequent, particularly compared to other surges.”

People who are at high risk of developing serious complications from COVID-19, such as organ transplant and cancer patients, are especially encouraged to take more precautions during the summer surge and avoid situations where they could be exposed to the virus, Grein said.

Those precautions include wearing a well-fitted mask indoors and in crowded areas, washing hands often and thoroughly, avoiding people who are sick, eating outdoors when possible, socializing in well-ventilated indoor areas, and for everyone—high risk or not—staying up to date on COVID-19 vaccinations.

The Centers for Disease Control and Prevention (CDC) reports that only 17% of the U.S. population has received the most recent bivalent vaccine, which was introduced in September 2022. An updated booster targeting the newer strain, Omicron subvariant XBB.1.5, is expected by fall 2023. The CDC has not yet recommended who should receive the newest booster.

“The vaccine may not prevent everyone from getting COVID-19, but it will certainly reduce your risk of becoming very ill,” Grein said.

If you do get sick, he added, test for COVID-19, stay home and rest. Also, he advised knowing in advance what treatment options are available if you test positive—especially if you’re at higher risk for severe illness.

“Let’s not forget the lessons we learned during the last few years of the pandemic about ways to stay safe,” he said. “We should continue to use the tools in our pandemic toolbox as this virus continues to wax and wane.”

Read more on the Cedars-Sinai Blog: Facts About Rebound COVID-19

What can you do to prevent ticks bites?

"There are several precautions to take before you hit the trails that can prevent bites, such as:

• Wear long-sleeved shirts and long pants. 
• Tuck the bottom of your pants into your boots or socks.  
• Apply tick repellent to clothing. Products with DEET will repel ticks and products with permethrin will kill ticks on contact.
• Avoid hiking in tall grass or heavily wooded areas because ticks tend to live and thrive in those areas.
• Try to hike in the center of the trail to reduce contact with ticks.

How do you check for ticks when you get home?

“The best place to inspect for ticks is in the shower. When you are inspecting your child check around the ears, near the hair line, under the arms, behind the legs and even inside the belly button because ticks like those crevices.”

How do you remove a tick?

“To remove a tick use a tweezer, and you want to apply the force of the tweezer at the base of the tick and  pull up. You don’t want to twist the tick off because you can leave parts of the tick inside embedded in the skin. If a tick is noticed within 24-hours of the hike or bite, and you are able to successfully remove it, the risk of transmission of any tickborne disease is very, very low.”  

What is the risk of Lyme disease?

“Thankfully, in Southern California, the risk of Lyme disease is much, much less than in other parts of the country, particularly in the Northeast. Most of the Lyme disease that we see here in Southern California actually comes from when a child or patient has traveled from the East Coast and they've been hiking there or have been in a summer camp, and they come back and they contracted Lyme disease from their exposure from these Lyme-endemic states in the Northeast.

“Ticks that carry the bacteria that cause Lyme disease can also carry other bacteria and cause infections known as Anaplasmosis and Ehrlichiosis. Symptoms of both can include fever, muscle aches, weakness and headache. Unlike Lyme disease, a rash is not as common. Symptoms usually occur one to two weeks after a bite from an infected tick. In both cases, they can be treated with proper antibiotics. Not every bite from an infected tick however, results in an infection.” 

What other bites do hikers need to watch out for?

"It's very important for parents to also understand that ticks are not the only thing that can bite you when you're out hiking in Southern California. We also often see infections that are caused by fleas. We call this "flea-borne typhus” and it is caused by a Rickettsial bacteria causing infection.  Animals that can carry these infected fleas include cats, wild possums, rats and mice. The infection is usually characterized by high grade fever, a rash as well as a bad headache. It's very important for parents to be aware that if their child goes hiking and has these symptoms, that could be from exposure to an infected flea.

Overall, the best advice is prevention, by wearing the right clothing and using repellents. But if you suspect someone in your family has a flea or tick infection, it’s important to let your doctor know you’ve been hiking to get the proper diagnosis."

Read more on the Cedars-Sinai Blog: Should You Exercise on the Beach?

The exercise is part of the Cedars-Sinai Special Pathogens Response Team’s efforts to bring its expertise in treating dangerous infectious diseases outside the walls of the medical center and into the broader community.

During the emergency drill, front desk staff, nurses, physicians and Environmental Services staff members will work together to diagnose the pretend patient, isolate them and don protective gear to keep themselves and other employees, visitors and patients safe. The care team will transfer the patient to a specialized ambulance, driven by first responders trained to handle highly infectious diseases. In a real-world scenario, the ambulance would swiftly transport an actual patient across town to Cedars-Sinai Medical Center.  

“We’re a community hospital, but we’re also the closest one to Los Angeles International Airport. We frequently see patients who acquire different kinds of infections while traveling abroad,” said Joseph Botros, who oversees Infection Control, Emergency Management and Environmental Health and Safety at Marina del Rey Hospital. “Working with the Special Pathogens Response Team is a top priority because we want to provide the highest quality of care to our patients while keeping our staff, visitors and other patients safe.” 

Botros said Marina del Rey Hospital employees are excited to participate in one of the special pathogens drills, which in the past have taken place only at the medical center’s Beverly Grove campus. He credited the COVID-19 pandemic with making staff members more engaged in planning for a public health crisis.

“COVID-19 was a huge turning point where everyone felt the importance of emergency management and how to work safely around infectious diseases. Our team members are eager to be a part of the solution,” Botros said.

In addition to collaborating with Marina del Rey Hospital, the Special Pathogens Response Team practices caring for patients in the community. In early June, the team members—dressed in their protective suits and respirators—left the medical center in an ambulance and rehearsed entering a resident’s home, staged inside the hospital’s Simulation Center. A mobile unit nurse and physician evaluated and tested a pretend patient who developed mild Ebola symptoms after traveling abroad.

The team practiced drawing blood from a manikin’s arm in a dining room while navigating the challenges of a normal house call—treating a patient in a nonclinical setting and dealing with a distracting pet.

“Unannounced, we simulated a dog barking,” said Jonathan D. Grein, MD, director of Hospital Epidemiology at Cedars-Sinai, who helped establish the team in 2016 as one of a dozen federally funded Regional Ebola Treatment Centers. “If a family had a pet dog, our protocol is to keep them in a different room and close the door because you don’t want a barking dog scratching at your personal protective equipment. It might seem trivial, but it’s important to practice navigating challenges we don’t normally encounter in the hospital.”

After gathering the blood sample, team members packaged it in a series of secure containers and handed it off to Los Angeles County Public Health professionals before sanitizing the pretend dining room.

“The team is always practicing new skills so that we’re better prepared to care for our community in any situation,” Grein said.

 Read more on Discoveries: Recipe for Disaster 

Although the names of these infections are almost identical—and their symptoms are very similar—they are completely different diseases. To clear up any confusion, we asked Jonathan D. Grein, MD, director of Hospital Epidemiology at Cedars-Sinai, to explain how these diseases compare to each other.

How does typhus differ from typhoid fever? 

Both diseases are infections, but they're caused by different types of bacteria that are spread in different ways. The kind of typhus we tend to see in the U.S. is spread by fleas that catch the disease from rats and opossums. Typhoid fever is spread through food that's come into contact with fecal bacteria. For example, a food worker might use the restroom, not wash their hands and then contaminate the food they're handling, which infects the person eating it.

What are the symptoms? 

The clinical symptoms can be very similar: fever, muscle aches, headache and, possibly, a rash on the trunk or back.

How can someone tell the difference between the two diseases? 

Symptoms like diarrhea or constipation are more commonly seen with typhoid fever than with typhus. A physician can make a diagnosis using different types of blood tests.

Why are the names so similar? 

People thought they were the same disease until the 1800s, when a physician determined that they were different infections.

How common are these infections? 

Los Angeles County sees an average of about 50 flea-borne typhus cases each year, except in 2018 when an outbreak caused that number to double. Typhoid fever, on the other hand, is less common in the U.S. It often manifests after a patient has traveled to Asia or India. The California Department of Public Health gets reports of about 75 cases of typhoid fever in the state each year.

How are these diseases treated? 

Fortunately, both infections are treatable. They each respond to different types of antibiotics.

How can people avoid catching these infections? 

You can reduce your risk of getting flea-borne typhus by avoiding contact with fleas. For example, make sure your pets are treated with flea protection. Also, keep rodents away from your home and workplace. You can avoid typhoid fever by getting vaccinated and carefully choosing what you eat or drink when you travel to countries where typhoid fever is more common. Speak with your doctor before you travel to see if a typhoid vaccine is appropriate. Stick to bottled water and fully cooked food or fruits and vegetables that must be peeled. Washing your hands also is important.

What should people do if they develop symptoms of these diseases? 

Contact your physician if you develop any of the symptoms like fever, muscle aches, headache and a rash on the trunk or back. Make sure you tell your healthcare provider if you've been traveling recently. A complete travel history could be critical to getting the right diagnosis.

Read more on the Cedars-Sinai blog: Typhus: What You Need to Know