The U.S. Centers for Disease Control and Prevention has formally classified the 2025-26 flu season as “moderately severe,” estimating it has already resulted in at least 11 million illnesses, 120,000 hospitalizations, and 5,000 deaths. The data shows activity is higher than the previous season, with a peak expected over the next few weeks.
How does this flu season compare to last year?
The current season’s toll is markedly higher than the same period last year. The CDC projected 5.3 million illnesses, 63,000 hospital admissions, and 2,700 fatalities by the end of December 2024.
This season’s numbers represent a more than doubling of illnesses and hospitalizations, prompting the “moderately severe” classification. The previous week alone saw about 33,301 new flu-related hospital admissions, a sharp increase.
What is driving the severe flu season?
Public health experts point to a combination of factors: substantial holiday travel, lower vaccination rates, and widespread misinformation about vaccines.
“Fewer people getting vaccinated and a partial vaccine mismatch are key reasons for the surge this year,” said Dr. Eric Ascher, a family medicine physician. The CDC notes that flu cases are always undercounted, as many people do not seek formal testing.
Which flu strain is dominant?
Influenza A(H3N2) remains the overwhelmingly dominant strain, responsible for more than 91% of subtyped influenza A cases.
Genetic analysis shows that 90.5% of the characterized H3N2 viruses belong to a specific variant known as subclade K. H3N2 seasons are often associated with more severe illness, particularly among older adults and young children.
When will the flu season peak expected?
Activity remains elevated and is still rising. “We’re not going to see the peak until at least another week or two,” Dr. Ascher noted. The CDC advises that flu activity will likely continue at high levels for several more weeks.
Outpatient visits for respiratory illness have risen to 8.2% of all healthcare visits, surpassing the national baseline. The CDC also reported one new pediatric flu death last week, bringing the season’s total to nine.
What should the public do?
The U.S. Centers for Disease Control and Prevention has formally labeled the 2025-26 flu season “moderately severe,” estimating it has already led to at least 11 million illnesses, 120,000 hospitalizations, and 5,000 deaths. The data shows activity remains higher than the previous season, with a peak expected over the next few weeks ahead.
The data, which shows a dramatic increase in hospitalizations as the virus spreads, highlights the pressure on the healthcare system.
