A cold is a viral upper respiratory tract infection that typically affects the nasal part of the respiratory system. The infection is usually mild and goes away without treatment. Symptoms may include a runny nose, headache, and sneezing. About half of patients can also experience a cough or sore throat. A cough that persists after other cold symptoms have cleared up may indicate bronchitis, sometimes called a chest cold, which is an inflammation of the airways in the lungs.

Colds are most common in winter and spring months, and usually last 7-10 days. You can help prevent a cold with frequent handwashing and by avoiding contact with people who have a cold.

Not a cold? Read, Why Am I Sneezing?

The flu is caused by the influenza virus and lasts about 5-7 days. Symptoms of seasonal flu typically include fever, fatigue, headache, and muscle aches. The best way to avoid getting the flu is by getting a flu shot, which takes about 2 weeks after injection to start protecting you from the flu virus.

"Get your flu vaccine before the flu season starts," says Dr. Kang. "This not only reduces your risk of the flu, it also protects more vulnerable people around you who may not have good immunity, such as the elderly, people with chronic illnesses, or small children."

Who should get a flu shot? According to Dr. Jonathan Grein, Cedars-Sinai’s director of hospital epidemiology, everyone 6 months or older should get an annual flu shot before flu season starts.

Read: What's the Difference Between a Cold, the Flu and COVID-19?

Colds and flu are not treated with antibiotics and rarely require a trip to the doctor. While the flu can occasionally be life-threatening for those with reduced immunity, for most people the best remedy for a speedy recovery from a cold or flu is usually rest and plenty of fluids.

Dr. Kang recommends seeking medical attention if you experience shortness of breath or trouble breathing, pain or pressure in the chest or stomach, dizziness when standing, decreased urination, confusion, inability to keep fluids down, or a fever lasting more than 48 hours. If you experience any of these symptoms, visit your primary care doctor or urgent care as soon as possible.

Read: Flu: When to Go to the ER