This year’s “super flu” season is certainly living up to its name.
The US is experiencing its highest infection rate in nearly three decades, according to flu statistics released by the CDC on Monday, with all but four states reporting increased levels of illness as the new virus strain subclade K continues to spread.
And New York appears to be getting hit the hardest: The week of Dec. 26, 2025, to Jan. 2, 2026 saw the highest number of flu hospitalizations recorded in a single week.
In the last week of December, the country saw a whopping 33% increase in positive flu tests.
And more than 8% of trips to the doctor were for sore throats and severe coughs — two trademark symptoms of this latest virus — up from last year’s number of 6.7%.
The number of sick people steadily increased throughout the holiday season and even started showing alarming numbers back in November, when subclade K was responsible for more than half of US flu cases.
But experts warn that we haven’t even hit the peak yet, as influenza “continues to increase across the country”, the CDC said Monday.
As of Dec. 27, 30 states from all regions have moved into the CDC’s highest tier of flu activity. Before the peak holiday season, only six states were considered to have high flu activity.
States from the East Coast, including Maine and New York, to the Midwest and the South all saw drastic spikes in only two weeks, between Dec. 13 and Dec. 27. Montana and Vermont were the two states with the lowest flu rates.
Outbreaks were also reported internationally in Canada, the United Kingdom and Japan, which saw over 6,000 cases and several hospitalizations of children.
Meanwhile, hospitalizations are at their highest since 2010, with experts worried the numbers will get worse as more people get sick.
“These viruses are serious, dangerous, and life-threatening,” Massachusetts Public Health Commissioner Dr. Robbie Goldstein said in a news release. “We are seeing children who are seriously ill, families grieving devastating losses and hospitals under capacity strain.”
What’s going on in New York?
That last week of December into early January, the New York State Department of Health reported 4,546 hospitalizations across the state — a massive increase from the week prior.
“Almost 1,000 more people were admitted to a hospital during this most recent seven-day period compared to the prior week,” said New York’s Acting Commissioner of Health Dr. James McDonald. “There is still time to get a flu shot, and remember, flu can be treated with antiviral medication if started within 48 hours of symptom onset [as] your doctor deems appropriate.”
The week before that had already seen more people visit the ER for flu symptoms than any other week in the previous 10 years.
Why are cases so high?
Fewer people are getting vaccinated according to CDC data, as public distrust continues to grow, especially under Health and Human Services (HHS) Secretary Robert F. Kennedy, Jr.
Only around 48 million adults have gotten a shot this year, down from the nearly 61 million back in the 2019-2020 flu season.
Vaccinations have also particularly decreased in children by 11% from the 2020 flu season, dropping to only 42% receiving a shot.
This data was published the same day HHS announced modified childhood vaccine schedules, with the recommendation that kids get flu vaccines after a consultation with a doctor.
But the vaccine is also proving less effective this season. That’s because every year, the flu mutates. Production of the vaccine begins six to nine months in advance, and it’s based on data and scientific predictions — but sometimes, those predictions fall short.
Usually, flu shots are 40% to 60% effective. This year, estimates are that it’s only 32% to 39% effective in adults. Fortunately, it’s fairing better in children with 72% to 75% efficacy.
“[The dominant strain is] not very well-aligned with the vaccine this year, which means there is potentially a larger proportion of the population that is susceptible to the flu,” said Neil Maniar, director of the master of public health program at Northeastern University.
The dominant strain this year is subclade K, a mutation of H3N2.
However, experts continue to recommend flu shots and stress that it’s not too late.
“We’re really at the beginning of the influenza season here in the US,” Dr. Andrew Pekosz, a virologist and professor at Johns Hopkins Bloomberg School of Public Health, said during a media briefing in December.
