Your Flu Shot May Protect Against COVID, Studies Suggest

Female doctor or nurse giving shot or vaccine to a patient's shoulder

Aside from wearing a mask, social distancing and practicing good hand hygiene, there is one thing you can do this fall that might lower your risk of contracting COVID-19: Get a flu shot. That's the conclusion of a new study, which found that hospital workers who had been vaccinated against the flu were less likely to be infected with coronavirus than those who didn't get the shot. Read on, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.

How might a flu shot protect you from COVID?

In the study, which was released in preprint form and has not yet been peer-reviewed, researchers in the Netherlands looked at hospital databases to gauge COVID infection rates among employees who had received the flu vaccine. They found that workers who had been vaccinated had a 39 percent lower chance of testing positive for coronavirus by June 1 of this year.

Why might this be? There's a growing body of scientific evidence about a concept called "trained innate immunity" — simply, that vaccines may boost the "first responders" of the immune system overall, helping them fight off a range of pathogens and diseases.

Take the results of the Dutch study with a grain of salt, however, and remember that correlation isn't causation. The study doesn't definitively prove that the flu vaccine is protective against COVID-19. The people in the Dutch study who received it might simply be more health-conscious and more likely to engage in healthy behaviors that lowered their risk of catching coronavirus.

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Other studies suggest link between flu shot, lower COVID risk

But, as Scientific American pointed out this week, other recent studies have found a potential connection between vaccines and a lower risk of COVID-19. In two papers published in June and September, researchers found lower COVID-19 rates in parts of Italy where more adults over age 65 had gotten the flu vaccine. And in July, researchers at the Mayo Clinic reported that adults who had gotten vaccines for flu, polio, chickenpox, measles-mumps-rubella (MMR), Haemophilus influenzae type B (Hib), hepatitis A or B, or pneumococcal disease over the past five years were less likely to test positive for COVID-19 than people who hadn't gotten any of those vaccines.

Whether this intriguing theory is ultimately proven or not, health experts advise that adults should get the flu vaccine every year. It's especially important during the coronavirus pandemic: It will lower your chance of being infected with the flu and COVID-19 at the same time, which can lead to worse outcomes; avoiding the flu can keep your immune system at its strongest; and you'll be less likely to need medical resources for the flu that may also be needed by people suffering from COVID and other serious illnesses.

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How to stay healthy

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: Mask, get tested if you think you have coronavirus, avoid crowds (and bars, and house parties), practice social distancing, only run essential errands, wash your hands regularly, disinfect frequently touched surfaces, and to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.