Overview
- CDC estimates as of Jan. 3 list at least 15 million illnesses, 180,000 hospitalizations and 7,400 deaths, including 17 children, with hospitals reporting sustained strain.
- Sequencing shows H3N2 now dominates and roughly 91% of characterized H3N2 viruses are the K subclade that differs from the vaccine strain.
- Preliminary University of Pennsylvania data indicate this season’s vaccine elicits measurable antibodies to subclade K, aligning with real‑world evidence of protection against severe disease.
- Some surveillance measures ticked down in early January, yet officials say elevated activity will persist for weeks and emergency visits and hospitalizations remain high.
- A human exposure study found limited spread in well‑ventilated settings with little coughing, while clinicians urge early antivirals for high‑risk patients and public‑health groups press vaccination despite recent changes to childhood guidance.