A woman holding a tissue to her nose during flu season.

Last winter’s flu season, one of the most severe in years, led to almost 80,000 deaths and almost a million hospitalizations in the U.S., according to estimates by the Centers for Disease Control and Prevention.

That makes the number of flu deaths significantly higher than the agency’s previous top estimate for a season—of about 56,000 deaths during the 2012 to 2013 season

New data released by the CDC suggest that low vaccination rates may have been a factor, though the agency cautions that these numbers are preliminary and could change. During the 2017 to 2018 season, the CDC estimates that just 37 percent of adults got a flu shot—a 6-point decline from the previous season. 

More on the Flu

There's no way to know exactly how bad the coming season will be, but you should get a flu shot now if you have not already—even though there are early signs that this season may be less severe.

Australia's flu season—which is coming to an end soon—has been very mild, especially when compared with 2017. And Australia is often seen as an indicator of how the flu might play out in the U.S., explains Jeffrey Shaman, Ph.D., an associate professor in the department of environmental health sciences and director of Columbia University’s Climate and Health Program.

But scientists emphasize that there’s no guarantee we’ll have a similar flu season to Australia’s—because flu is highly unpredictable.

“We want everyone to look at every flu season as if it’s going to be a bad flu season,” U.S. Surgeon General Jerome Adams, M.D., M.P.H., said at a media event in September. The best way to prepare, he says, is a flu vaccination.

Here’s what you need to know about flu season, and what you can do to protect yourself.

Why Was Last Flu Season so Severe?

Different strains of the flu tend to predominate in different years of flu season. During the 2017 to 2018 season, a virulent strain of influenza called H3N2 was mostly responsible for the high number of flu cases.

The strain is associated with more cases of the flu, more hospitalizations, and more deaths than other strains, according to Dan Jernigan, M.D., M.P.H., director of the CDC’s influenza division.

The flu vaccine was also only about 25 percent effective at preventing infections from H3N2 last year—but 36 percent effective at preventing flu overall. 

Smart Steps to Prevent Flu

For almost everyone over 6 months of age, getting vaccinated against the flu is the most effective way to safeguard yourself and those around you, experts say.

If you haven’t gotten your flu shot already, the CDC recommends doing so soon—ideally before the end of October so that you’re well-protected when flu season peaks, usually sometime between December and February. It takes about two weeks after receiving the vaccine for immunity to fully kick in.

This absolutely includes pregnant women—only about half of whom received flu shots during the 2017 to 2018 season, according to data from the CDC. The flu can be especially dangerous for pregnant women because their immune systems don’t work the way the systems normally do, says Laura Riley, M.D., director of obstetrics and gynecology infectious disease at Massachusetts General Hospital, who spoke at a media briefing in September. “Pregnant women who get the flu do very poorly,” she says, and notes that the flu shot is safe for expecting mothers.

Even though last season’s vaccine was imperfect, you should still get your shot each year. “Some effectiveness is better than no effectiveness,” Adams says. And even if you get the flu shot but still get the flu later, you’re less likely to become seriously ill or be hospitalized. Most children who die from flu are unvaccinated.

In addition to getting the flu vaccine, our medical experts offer these three tips for avoiding germs this time of year:

1. Because dry air helps the flu virus live longer, consider using a humidifier to keep humidity at 30 to 50 percent.

2. Avoid touching your nose and eyes, to reduce the chance of transferring any virus you might have on your hands.

3. Wash your hands often. Use soap and water, and rub hands together for at least 20 seconds. When soap and water are not available, use a hand sanitizer with at least 60 percent alcohol.

What to Do If You Get the Flu

Rest and keep yourself hydrated. If you have fever, headache, and achiness, opt for acetaminophen (Tylenol and generic), ibuprofen (Advil and generic), or naproxen (Aleve and generic).

Ask your doctor for a prescription for an antiviral medication right away if you develop a fever, cough, and body aches, and you’re 65 or older, obese, or have a compromised immune system or a chronic health concern. Your pediatrician might recommend antivirals for children who have severe flu or a chronic health condition, such as asthma, diabetes, or heart or lung disease.

An antiviral medication can shorten the flu by one to three days, ease symptoms, and cut the risk of complications, but only if you start it within 48 hours of getting sick.

Avoid cough suppressants (flu coughs usually go away on their own) and antibiotics, which don’t work for viral infections and can contribute to antibiotic-resistant bacteria.

See your doctor if your flu symptoms start to improve but then fever returns and your cough worsens, or if you experience difficulty breathing, pain in the chest or abdomen, dizziness or confusion, or severe or persistent vomiting. 

For more treatment tips, see our guide to treating cold and flu symptoms.