U.S. flu infections surged over the holidays, and U.S. health officials warned Monday that the season is already approaching or surpassing last winter’s worst levels and could worsen.
New government data posted Monday covered flu activity through the week of Christmas and showed that, by some measures, this season is already surpassing the flu epidemic of last winter, one of the harshest in recent history.
Forty-five states were reporting high or very high flu activity during the week of Christmas, up from 30 states the week before. Public health experts said the higher numbers appear to be driven by the type of flu spreading.
One flu virus, called A(H3N2), has historically caused the most hospitalizations and deaths in older people. So far this season, A(H3N2) has been the type most frequently reported, and more than 90% of the A(H3N2) infections analyzed were a new version known as the subclade K variant that differs from the strain in this year’s flu shots.
Flu seasons often don’t peak until January or February, so officials said it is too early to know how big a problem the mismatch will be. Dr. Robert Hopkins, medical director of the National Foundation for Infectious Diseases, said the trend suggests the peak may still be ahead.
“The fact that we’ve seen steady increases over the last several weeks without much of a decline or even a flattening would suggest to me that we’ve got the peak ahead of us,” Hopkins said.
Officials also pointed to the fact that last flu season was already severe. They said the overall flu hospitalization rate was the highest since the H1N1 flu pandemic 15 years ago, and that child flu deaths reached 288, the worst recorded for a regular U.S. flu season.
Nine pediatric flu deaths have been reported so far this season. For children, officials said the percentage of emergency department visits due to flu has already surpassed the highest mark seen during the 2024-2025 season. Hopkins said A(H3N2) typically hits older adults hardest, but rising rates among children and young adults suggest a severe season across all age groups.
Another sign, officials said, was that the percentage of doctor’s office and medical clinic visits due to flu-like illness was higher late last month than at any point during the previous flu season. Deaths and hospitalizations had not yet reached last year’s levels, Hopkins said, describing those as lagging indicators.
The Centers for Disease Control and Prevention estimates at least 11 million illnesses, 120,000 hospitalizations and 5,000 deaths from flu have already occurred this season.
The warnings on flu come the same day that federal officials announced changes to vaccine guidance and immunization reporting. Public health experts generally recommend that everyone 6 months and older get an annual influenza vaccine, but federal health officials said Monday they will no longer recommend flu vaccinations for U.S. children, saying the decision should be made by parents and patients in consultation with their doctors.
A U.S. Department of Health and Human Services spokesperson said flu vaccine will continue to be fully covered by private insurers and federal programs, including Medicaid, the Children’s Health Insurance Program and the Vaccines for Children program.
Other federal data showed COVID-19 infections are rising, though officials said they remain less common than flu this winter. The Trump administration stopped recommending COVID-19 shots for healthy children last year, officials said.
Hopkins also voiced concern about a federal notice posted last week that said government Medicaid programs will no longer have to report on immunization rates. He said CDC survey data suggests U.S. flu vaccination rates are about the same as last year, but that Medicaid data provides a more comprehensive look at children at higher risk for many diseases.
Federal health officials framed the move as part of an effort to distance how Medicaid doctors are rated and paid from how often they provided childhood vaccinations. Health Secretary Robert F. Kennedy Jr. wrote that government bureaucracies should “never coerce doctors or families into accepting vaccines or penalize physicians for respecting patient choice,” adding, “That practice ends now.”
Hopkins, however, said the change will “eliminate a major source of data” that allows communities to assess efforts to protect children from vaccine-preventable diseases. He called it “a disastrous plan.”
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