En español | With COVID-19 in the spotlight, it may be easy to overlook the other potentially deadly virus going around this time of year: influenza, or flu. Flu season officially runs from October through May, which makes now a good time to arm yourself with real facts about the virus that claims tens of thousands of lives — a majority of them older adults — every year. Here, we correct seven common flu myths to help you strengthen your defenses.
Myth No. 1 Cold weather causes flu
Viruses cause flu, not cold weather. What is true, says David Hooper, M.D., chief of the Infection Control Unit at Massachusetts General Hospital in Boston, is that the influenza virus survives better in colder environments. What's more, “during colder weather, people tend to gather inside with closed windows and less air circulating, causing higher risk of flu spread,” he says. Additionally, lower temperatures may negatively affect the immune response, which makes us more vulnerable to flu, which spreads via droplets as people around us talk, sneeze or cough.
Myth No. 2 Flu is just a bad cold
Not every respiratory illness is the flu, notes Waleed Javaid, M.D., director of Infection Prevention and Control at Mount Sinai Downtown in New York City. While flu and the common cold can have similar symptoms, they are caused by different viruses. And they each possess distinct symptoms, too. Cold, for instance, may give you a runny or stuffy nose; influenza usually doesn't. And while a cold can make you feel lousy, the flu “can make you feel like you were hit by a train,” Javaid says. In addition, colds rarely lead to dangerous complications, whereas “a bad case of flu can travel to the lungs and cause serious infections,” says Arun Karlamangla, M.D., a geriatrician at UCLA Health.
Myth No. 3 Antibiotics can help treat flu
Flu is a viral infection. Antibiotics treat only bacterial infections, like strep throat or urinary tract infections. Sometimes, says Javaid, complications from flu, such as pneumonia, are treated with antibiotics, but flu itself is not. For flu, in addition to over-the-counter drugs for, say, relieving coughing and stuffy nose, there are approved antiviral drugs, such as Tamiflu. (One note: These antiviral drugs should be taken early in the onset of flu symptoms to be effective.)
Myth No. 4 You don't need a flu vaccine if you rarely get sick
Flu is highly contagious, and yes, even healthy people get it. “The influenza vaccine is the very best intervention we have to prevent flu infections and, sometimes, the serious complications it can cause,” stresses Lisa Maragakis, M.D., senior director of infection prevention at the Johns Hopkins Health System. “Everyone should get a flu shot every year, and in the midst of the COVID-19 pandemic it becomes even more important.”
What's more, the flu virus “can mutate from season to season,” says Sophia Tolliver, M.D., clinical assistant professor of family medicine at the Ohio State University Wexner Medical Center. If a strain circulates that your immune system has no experience fighting, you can be more susceptible to getting sick. Getting a flu shot will help, Tolliver notes, since the shot is designed to build immunity to the specific strains circulating in a given season.
Myth No. 5 The flu shot can make you sick
There is no active virus in the flu vaccine, so it can't cause flu. Your arm may hurt after getting the shot, but such pain likely won't last long, says Ankita Sagar, M.D., a primary care physician at Northwell Health in Great Neck, New York. Also, your body may ache as it's building up immunity, she says. All of which is likely worth it: According to the Centers for Disease Control and Prevention (CDC), the influenza vaccine stopped an estimated 4.4 million influenza illnesses in the especially severe 2018-2019 flu season, preventing 2.3 million flu-related medical visits, 58,000 flu-related hospital stays and approximately 3,500 deaths.
Myth No. 6 You might also catch a “stomach flu"
The word “flu” is often used incorrectly for a variety of unrelated viruses and other illnesses. For one, while influenza can sometimes cause gastrointestinal symptoms, Maragakis says, a stomach bug that causes the sudden onset of nausea, vomiting or diarrhea is not the flu. The term “stomach flu” is used loosely to refer to viral gastroenteritis, which is not caused by influenza virus, but other viruses, such as norovirus. Norovirus infections can occur at any time of the year, but outbreaks usually happen from November to April, coinciding with influenza virus.
Myth No. 7 Once you have a flu shot, you won't get the flu
After you get the vaccination, it can take up to two weeks for immunity to be generated in the body, says David Hirschwerk, M.D., an infectious disease specialist at Northwell Health in Manhasset, New York. And a flu shot is not 100 percent effective at preventing the flu, he says. That said, vaccination will make any symptoms you do get less severe. Adds Sagar, “Your risk of being admitted to critical care is markedly less if you get a flu shot.” And that, Hirschwerk adds, is especially important to help lessen the strain on the health care system during the COVID-19 pandemic.