Overview
- CDC surveillance indicates elevated influenza activity that continues to rise nationwide.
- Season-to-date estimates exceed seven million illnesses, about 81,000 hospitalizations and roughly 3,100 deaths, with a sharp week-over-week jump in late December.
- H3N2 subclade K now predominates in sequencing, showing high transmissibility without clear evidence of increased clinical severity.
- New York reported 71,123 lab-confirmed cases in the week ending Dec. 20, the highest weekly total since 2004, and state hospitalizations rose 63% in the same span.
- Argentina confirmed an imported H3N2 subclade K case in Mendoza in a 74-year-old traveler from Spain, verified by the Malbrán institute, and activated epidemiological monitoring with no community spread detected.