This year’s flu season could be a rager. Shots can help.

Last year was a record low for influenza, but this year could be tougher.
A small child is having a bandage put on his arm after receiving a shot. A caregiver stands behind him.
Kids under 5 should be able to get vaccinated against COVID within weeks. CDC

As summer winds down and gives way to cooler weather, people are once again bracing themselves for an uptick in COVID-19 cases—viruses like SARS-CoV-2 prefer colder seasons. But there’s another virus looming that’s all-too-familiar: influenza. 

Now, two new study preprints, neither yet peer-reviewed, suggest that last year’s drop in flu cases could lead to a high resurgence of flu this season due to lower immunity against influenza across communities. A 25 to 50 percent increase in flu vaccinations this year, one study says, could prevent that upswing.

Last year was a record low for the flu. The US Centers for Disease Control and Prevention (CDC) report that the 2020-2021 flu season yielded just one child death by the flu—an incredible dip from the previous low of 37 (during the 2011-2012 season) and the 2019-2020 record high of 199. But public activity in the US today is significantly higher than this time last year, when the majority of adults were still not vaccinated and many were spending their time masked or at home. As people slowly return to old routines and habits, health experts are worrying about a resurgence of the flu, and urge people to get a flu shot if they can. 

[Related: No, you can’t get the flu from a flu shot]

People should get vaccinated for the flu every year, but it’s especially important now given that COVID-19, another respiratory illness, is still spreading, said David Hirschwerk, an infectious disease specialist at Northwell Health in New York, to ABC News. He added that children in particular should be vaccinated, as it “helps to reduce risk of infection, of severe complications from flu, and it protects the entire household and communities by reducing transmission to others.”

The CDC emphasizes how much we still do not know about COVID-19, stating that “because COVID-19 is still a relatively new illness, we have little information about how flu illness might affect a person’s risk of getting COVID-19.” We do know, however, that “people can be infected with flu viruses and the virus that causes COVID-19 at the same time.” The bottom line, they say, is that getting a flu vaccine and a COVID-19 vaccine is the best protection against those two respective illnesses. 

There’s also no evidence to suggest that a flu vaccine makes you more vulnerable to COVID-19. In a recent paper in Pediatrics, a committee on infectious diseases writes that they recommend full flu vaccination in children by the end of October—if it’s a child’s first time getting vaccinated for the flu they’ll need two shots, otherwise they can just get one. Kids can still get the vaccine even if they’ve contracted SARS-CoV-2 if their symptoms are mild or if they’re on the mend—only children under 6 months of age or those with known allergies to vaccine ingredients should go without it. 

“The ‘twindemic’—a coinciding flu and COVID-19 epidemic—overwhelming our hospitals was thankfully avoided last year. But that does not mean it is no longer possible,” said Mark Roberts, director of the Public Health Dynamics Laboratory at Pitt Public Health and senior author on the two recent preprints, in a statement. “If anything, our models show that we should be more concerned this year about the possibility of a surge in COVID-19 hitting at the same time as a massive flu outbreak in areas of the country with low vaccination rates against both diseases.”

To prevent these parallel surges, vaccination for both diseases, influenza and COVID-19, is pivotal. But beyond getting your shots, experts want people to continue being diligent with their hygiene practices like earlier in the pandemic. “Mask-wearing has significantly curbed the spread of influenza,” Eric Cioe-Pena, an emergency medicine specialist at Staten Island University Hospital, told ABC News. “Wash your hands, wipe down commonly touched surfaces like keyboards, phones and door knobs. Stay home when you are sick, and wear a mask.”