US flu virus cases rise, CDC officials warn of severe season

AP News•January 5, 2026•health

Key Points:

U.S. flu infections surged over the holiday season, with 45 states reporting high or very high flu activity by Christmas, up from 30 states the previous week, indicating a severe flu season likely to worsen.
The predominant flu strain this season is A H3N2, which historically causes more hospitalizations and deaths in older adults; over 90% of cases are a new subclade K variant that differs from the strain included in this year’s flu vaccine.
Flu activity has already surpassed levels seen during last season's severe outbreak, with pediatric flu deaths and emergency visits for flu-like illness exceeding previous peaks early in the season.
The CDC estimates at least 11 million flu illnesses, 120,000 hospitalizations,