It’s no wonder, then, that within households, if one person comes down with the flu, there’s a good chance others will wind up sick too. One study found, for example, the risk of flu spreading within a single dwelling is around 38 percent. Families, roommates, and others who live together can beat those odds, though, starting with annual flu vaccines all around for every household member who’s eligible for one. But given that getting a flu shot isn’t a guarantee you won’t get sick (the vaccine is around 40 to 60 percent effective), taking other precautions to prevent the flu from spreading is prudent.

1. Wash Your Hands

Do it frequently and fervently. That means after sneezing and coughing, coming in from outside, shaking hands, and especially before eating or touching your face or someone else’s, urges Mike Hoaglin, MD, medical advisor for DrHouse and supervising virtual care physician at Oscar Medical Group and Brightside Health in San Francisco. To make sure your hand-washing routine is effective, the Centers for Disease Control and Prevention advises using warm water and soap and taking care to lather the backs of your hands and between your fingers for at least 20 seconds. (An easy way to count it out is to sing the “Happy Birthday” song twice.) Use a fresh towel, preferably a paper towel, to dry your hands completely.

2. Isolate

“Many infection control measures we learned during COVID apply to influenza,” notes Laura Purdy, MD, chief medical officer at OpenLoop telehealth platform and a family physician in Fort Benning, Georgia. If you have flu symptoms, test positive for flu, or even suspect you may have been exposed to someone who’s sick, put as much space as possible between you and the people you live with (and have others do the same if the flu is on the other foot, so to speak). If there’s a bedroom or other spare room available, that’s ideal, especially if someone is able to deliver meals and other must-haves. At the very least, advises Dr. Hoaglin, stay away from common areas for at least three or four days, when the virus is most contagious. Whoever the designated caregiver turns out to be, it’s important they take every precaution to protect themselves — even if they’ve already had the flu. “I’ve been surprised by the number of people who catch the flu more than once in a season,” says Dr. Purdy.

4. Gear Up

As with the COVID virus, one of most effective ways to prevent the spread of influenza is by wearing a mask — preferably an N95 mask, advises Michael Roizen, MD, chief wellness officer emeritus at Cleveland Clinic in Ohio. That goes for anyone who is sick, to keep their viral droplets out of the air, and for those who are well, to shield themselves. If you’re caring for a child or someone else who has flu, slipping on disposable gloves is a good idea too, as it will lower the risk of picking up the virus with your fingers and then touching your eyes, mouth, or nose.

5. Clear the Air

Proper ventilation of common spaces and individual rooms is important, says Hoaglin. Whether you crack a few windows or plug in an air purifier, it can help reduce the volume of infectious particles in the air. Consider doing this even before someone comes home sick, as well as when you have a gathering of people.

6. Keep Things Clean

The flu virus can live on hard surfaces for up to 48 hours, meaning everything from countertops, doorknobs, and cell phones to TV remotes, drinkware, and eating utensils —especially those touched or used by someone who’s ill. Make use of disinfectant wipes, sprays, and other cleaning solutions that contain hydrogen peroxide, chlorine, and/or alcohol, which can kill germs immediately and on contact. Stash alcohol-based cleaners throughout your home so they’re handy for everyone, suggests Hoaglin.

7. Trash the Virus

Studies show the influenza virus can survive for 8 to 12 hours on cloth and paper. Consider a temporary switch from hand towels and dishcloths to single-use paper products. Then take care to dispose of used paper products promptly by tossing them into a trashcan, preferably one lined with a plastic bag, and don’t set them down anywhere or let them come in contact with someone else.

8. Do an Immune System Boost

Some simple ways to help fight off infection are also healthy lifestyle measures. One is to stay well-hydrated, which supports the circulatory system in delivering nutrients to organs throughout the body and to remove waste products — including potentially infectious microbes. The U.S. National Academies of Sciences, Engineering, and Medicine recommends males get about 15.5 cups of fluid each day and females get 11.5 cups. Not all fluid needs to be water, according to the Mayo Clinic. Non-caloric beverages, including coffee and tea, count too, as do juicy fruits and veggies and fluid-based foods such as soup. Vitamin C may help as well. Although the once-popular theory that high doses of C may help prevent or cure the common cold has never been proven, there is evidence C may be able to kill influenza A and other viruses. And it can never hurt to include plenty of C-rich foods in your diet: citrus fruits, bell peppers, strawberries, tomatoes, white potatoes, and broccoli, cabbage, and other cruciferous vegetables. Consider (carefully) catching some rays as well, to boost your intake of vitamin D, which plays a key role in shoring up the immune system. The National Institutes of Health advises wearing sunscreen with an SPF of at least 15 if you’re in the sun longer than a few minutes, and eating plenty of D-dense foods, such as fortified dairy products, fatty fish, and even mushrooms: Sometimes the fungi are exposed the ultraviolet light to boost their vitamin D content.