Here’s even more reason to get a flu shot: This year’s flu season is expected to be a bad one, potentially even worse than last year’s record-breaking season.
Last year was the worst flu season in 15 years for the United States, with high hospitalizations and infection levels.
“We also saw the highest number of pediatric flu deaths that we’ve seen since 2009-2010,” said Dr. Robert Hopkins, the medical director of the National Foundation for Infectious Diseases.
No one wants a repeat of last flu season, but we may be on track for that. Here’s what to know:
Flu season is off to a bad start in the U.K., and experts think that could happen here, too.
According to BBC reporting, experts in the U.K. predict the country will have a severe flu season, too, based on an early start to the flu season there, along with a mutation in the flu virus. This isn’t good news for respiratory virus season anywhere, including in the U.S.
“We do generally see similar patterns in North America, as we see in Western Europe,” said Dr. Daniel Kuritzkes, the chief of the division of infectious diseases at Brigham and Women’s Hospital in Boston. “So, it is likely that we’ll see a similar flu season here to what’s being experienced currently in the U.K.”
Derek Smith, the director of the Centre for Pathogen Evolution at the University of Cambridge, told the BBC that mutations in the H3N2 flu strain are causing a “fast increase” in cases.
Based on the latest data from the Centers for Disease Control and Prevention, the H3N2 strain is in the U.S., too, and is currently the most “frequently reported” influenza virus in the country.
“It has undergone some changes and some mutations, a fairly significant number of mutations, so … it is likely to cause a problem,” said Dr. Jill Foster, a professor at the University of Minnesota Medical School.
“The flu virus that is circulating does appear to be more pathogenic. It is more easily transmitted, and when transmitted, causes more severe disease,” Foster said.
And if COVID has taught us anything, it’s that viruses don’t stay within country borders, Foster noted.
To predict the severity (or not) of flu season in the U.S., experts glean influenza data from countries in the Southern Hemisphere, where the flu season occurs during our summer months (Australia, for example, had a record high number of flu cases this year), along with European countries, where flu season starts a little earlier.
Flu season has also started early in Japan and Canada, Hopkins added. “You put that together with the reports of these mutations in the H3N2 influenza that were detected back this summer, all are concerning for potentially a second severe flu season in the U.S. in a row,” Hopkins explained.
Foster agreed. “All of that leads you to a place of saying that it is likely that we are going to have a worse flu season.”
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The good news, for now, is that flu rates in the U.S. are currently low.
The CDC updates flu activity weekly, but that wasn’t happening for much of the fall because of the government shutdown. Now, though, that data is back online.
Individual states also track illnesses, but the level of tracking varies. When looking at state-by-state data, including in his own state of Massachusetts, flu rates are also not yet elevated, Kuritzkes said.
Hopkins agreed. “Based on the city and state level surveillance … cases appear to be fairly low and similar to the same time the last couple of seasons.”
This doesn’t mean there’s no flu in the U.S., though. Southern states and states including Arizona and New York are starting to see a small uptick in flu cases, according to epidemiologist Caitlin Rivers’ Substack.
“We’re not seeing any surge in cases so far, which would suggest that if we are going to look like what England is looking like, there’ll be a lag,” Kuritzkes said. In the U.S., cases don’t increase too much until December and then tend to peak in January or February, with a second peak in March.
Flu shots protect people from severe outcomes like hospitalization and death.
Each year, the flu vaccine is updated to offer the best possible protection against the flu strains that are expected to be dominant that season, but this new flu virus strain emerged after experts selected the strains for the current year’s flu vaccine, Hopkins said.
Meaning, this year’s flu vaccine doesn’t match this new, mutated virus strain.
“It is certainly concerning that a new strain has emerged that seems to be somewhat divergent from the strain against which the vaccines were selected,” Kuritzkes said.
But that doesn’t mean the vaccine is not important. It remains the best way to protect yourself. “Even if the vaccine is not a perfect match, there are many reasons that people should get the flu vaccine if they haven’t done so already,” Kuritzkes noted.
Boosting your flu immunity may not mean you won’t get infected with the flu this winter, but if you do, “it’s likely that the flu you get will be less severe than if you’re unvaccinated,” according to Kuritzkes.
Approximately 89% of children who died of flu in 2024-2025 were not fully vaccinated, which shows the importance of the protection that vaccination offers.
Last flu season, only about 47% of adults received a flu shot in the U.S. Data for this year is not yet available (again, because of the shutdown), but Foster is nervous about what vaccine hesitancy could mean for shot uptake.
“There’s been so much confusion and so much disarray in pushing out vaccine recommendations this year that I would not at all be surprised to see that flu vaccine uptake in this country is less this year than usual, and if it is, then we’re really in trouble,” Foster said.
Unvaccinated people are more likely to die or end up in the hospital from flu and are more likely to have severe disease that spreads to others for longer, Foster added.
“Second, even if [H3N2] is the most concerning one, there are typically several strains that circulate,” Kuritzkes said. Just because the vaccine isn’t a perfect match for the new strain doesn’t mean it won’t be for future flu strains, added Kuritzkes.
While it’s easy to panic over headlines about an upcoming severe flu season, Hopkins said to prepare instead of panic.
“Make sure that you have fever-reducers around the house, make sure that you keep plenty of fluids around the house, get some over-the-counter COVID and flu tests, so that if you are sick, you can test and let your health care professional know what you got,” Hopkins explained.
There are antiviral medications your doctor can prescribe for flu (and COVID) that can help reduce the severity of your illness.
To protect yourself and others, wash your hands frequently, cough or sneeze into your sleeve — and, if you have kids, encourage them to do the same. Wearing a mask in crowded indoor spaces can also protect you from the flu, along with other viruses.
“Let’s do the things we can to reduce our risk for either giving or getting any of these viruses,” Hopkins said.
Babies and older adults are most at risk for severe outcomes from the flu, so take extra care if you are around folks in these age groups, Foster said.
“I think it’s important that we recognize we’re all in this together. When I think about protection against any of these viruses, I think about not only protecting myself and my family, but I also think about the people around me,” Hopkins said. “If we prevent illness in our community, we reduce the likelihood that we’re going to get ill, and we reduce the impact on our community and on our health care workers around us.”
This story has been updated to reflect the most recent CDC flu data, which was originally unavailable at the time of publishing.
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