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How Will COVID-19 Affect Flu Season?


This story has been updated as of 9/23/21 at 9:12 a.m. PT.

Q&A with Infectious Disease Specialist Rekha Murthy, MD

With flu season fast approaching, health officials are urging the public to help contain the spread of influenza and avoid another outbreak amid the ongoing COVID-19 (coronavirus) pandemic.

"The two viruses are very similar, and it's going to make this flu season very challenging," said infectious disease specialist Rekha Murthy, MD, vice president of Medical Affairs and associate chief medical officer at Cedars-Sinai. "The good news is we have a powerful tool at our disposal to combat influenza — the flu shot."

In addition to getting the flu vaccine, it's critical to remain vigilant about safety measures that can prevent the spread of the flu and COVID-19: sanitizing hands, wearing masks, physical distancing, covering coughs and sneezes, and staying home when sick.

"The choices we make not only affect our own health but the health of others as well," Murthy said. "Many people may be feeling pandemic fatigue, but we need to protect ourselves and everybody around us."

For more details on what to expect during this flu season, the Newsroom spoke with Murthy about how to prepare and protect yourself in the months ahead.

How will I be able to tell if I have the flu or if I have COVID-19?

Symptoms of COVID-19 and the flu can range from mild to severe. It's very hard to distinguish between the two illnesses, and there are a lot of overlapping symptoms:

  • Fever or feeling feverish/chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Sore throat
  • Runny or stuffy nose
  • Muscle pain or body aches
  • Headache

However, there are some precursors to COVID-19 — loss of taste and smell, nausea and/or diarrhea — that appear to be less associated with the flu. The onset of the flu can occur much more quickly. Individuals typically will experience symptoms one to four days after exposure to the virus. With COVID-19, symptoms appear an average of five days after exposure.

What should I do if I develop symptoms that could be related to the flu or COVID-19?

If you develop the overlapping symptoms, it's going to be important to recognize early that you could have either illness, to be aware of what symptoms you've been experiencing, and to determine when to seek testing or medical care. You should isolate yourself for at least 10 days or until your symptoms resolve or you see your doctor. It will be important not only to care for yourself but to protect those around you.

If your symptoms don't improve, or you're feeling worse, call your healthcare provider. You can be tested for both COVID-19 and the flu. If you develop worsening symptoms, visit urgent care. Go to the emergency department if you experience severe or life-threatening symptoms, including trouble breathing, persistent pain or chest pressure, sudden confusion, sharp decline of energy, bluish lips or face, or a child under 8 weeks old with a fever.

How can I protect myself during flu season this year?

Everyone who is over six months of age should get the flu vaccine. It can prevent you from getting the flu, and if you do become ill, it can reduce the severity and duration of your illness. If enough people get vaccinated, it can help avoid a so-called "twindemic" in which the healthcare system is overwhelmed with patients suffering from COVID-19 or the flu. Getting the flu shot also reduces unnecessary COVID-19 testing and helps healthcare workers identify COVID-19 patients more effectively.

We also need to double down on the safety measures that can prevent the spread of COVID-19 and the flu: hand-sanitizing, wearing masks, physical distancing, covering coughs and sneezes, and staying home when sick.

Are there any other ways I can prepare?

Make sure you have fever-reducing medication, such as acetaminophen, at home, and drink plenty of fluids if you get sick. If you haven't already established a relationship with a primary care provider, do so now. They can administer your flu shot and treat you if you become ill. Many offer virtual video visits that allow for efficient appointments from the comfort of your home. While most COVID-19 treatments are still considered experimental, there are antiviral medications readily available that your physician can prescribe to treat the flu.

Should people at high risk for severe illness from COVID-19 get the flu shot?

Absolutely. Vaccination of more vulnerable individuals is especially important because it decreases their risk of developing a severe case of the flu. Many people at higher risk for flu complications also seem to be at higher risk for COVID-19. Everyone should get the flu shot this year, including pregnant women, children over six months of age, older adults and people with underlying medical conditions. Try to get the vaccine as early as possible before flu season fully gets underway in November. It takes two weeks for your body to develop its full immune response once you receive the vaccine.

If I'm pregnant, am I — or my baby — more susceptible to the flu or COVID-19?

Pregnant women and their babies run a higher risk of suffering complications due to the flu or COVID-19. That's why it's important that pregnant women follow all the safety precautions and get the flu shot.

Where can I safely get the flu shot during the pandemic?

Vaccines should be available at your physician's office and pharmacies. Ask these providers if they are following the pandemic vaccination guidance issued by the Centers for Disease Control and Prevention (CDC). The guidance lists precautions that should be observed in healthcare settings: screening for COVID-19 symptoms, physical distancing, wearing appropriate personal protective equipment, and taking other safety measures. Any vaccination location following the CDC’s advice should be a safe place for you to get a flu shot.

Rekha Murthy, MD
If enough people get the flu vaccine, it can help avoid a so-called "twindemic" in which the healthcare system is overwhelmed with patients suffering from COVID-19 or the flu.
Rekha Murthy, MD

Is it safe to come to a Cedars-Sinai clinic to get my flu shot?

Yes. Cedars-Sinai continues to implement safety precautions to ensure our facilities, including flu clinics, are safe. These measures include screening and temperature checks, universal masking, physical distancing, and thorough cleaning and disinfection of public spaces and equipment. Cedars-Sinai also continues to monitor the latest COVID-19 data and coordinates closely with public health authorities to ensure maximum protection for our patients, visitors and staff members as the pandemic evolves.

Will the flu shot offer any protection against COVID-19?

Unfortunately, it will not because the flu and COVID-19 are caused by different viruses. Vaccines are designed to help you develop immunity to the components of a specific virus. Potential vaccines for COVID-19 are still in development and may not be available until late in flu season or even after it ends in early spring.

Could the flu vaccine make me sick and more vulnerable to COVID-19

The flu vaccine is extremely safe. It does not contain live virus. There is no evidence that getting the vaccine increases the risk of contracting COVID-19. Some individuals may experience mild side effects — local swelling, discomfort, low-grade fever or headache — that resolve within a couple of days and pale in comparison to the actual flu.

Is it possible to have COVID-19 and the flu at the same time? If so, what do I do?

Yes. It is possible to have both illnesses — and other respiratory infections — at the same time, which is another good reason to get vaccinated against COVID-19. It's not yet clear how often that could happen. Promptly contact your doctor if you experience symptoms related to either illness.

I am waiting for COVID-19 test results. Should I wait to get a flu shot until I get the results?

Yes, you should wait until you get a negative test result. If you test positive for COVID-19, you should wait to get the flu shot until your symptoms resolve and it's safe to discontinue isolation. In the meantime, follow all protective measures to limit your exposure to the flu.

If I had COVID-19, am I more susceptible to the flu? Or am I protected against the flu if I had COVID-19?

There is not enough data to suggest that you'd be more likely to get the flu because you had COVID-19. Because these illnesses are caused by different viruses, there is no evidence to suggest that a previous COVID-19 illness would confer any protection or immunity against the flu.