Summary
A new flu virus strain, H3N2 subclade K, is causing most flu cases in the United States this season, leading to numerous hospitalizations and deaths. Although the strain spreads quickly, it doesn't appear to cause more severe illness than other flu viruses. The current flu vaccine is not perfectly matched to this strain but still offers protection, especially against severe illness.
Key Facts
- The H3N2 subclade K flu strain is dominant in the U.S. this flu season.
- The flu season has resulted in about 4.6 million illnesses, 49,000 hospitalizations, and 1,900 deaths nationwide.
- Subclade K is a variant of influenza A and was first identified by the CDC in August.
- This strain has undergone antigenic drift, meaning it has changed genetically over time.
- About 89% of H3N2 samples tested since late September are subclade K.
- Dr. Parth Bhavsar noted that subclade K is not linked to more severe illness than other flu strains.
- Typical symptoms include fever, body aches, cough, and fatigue.
- Despite some differences from the vaccine strain, flu vaccinations still provide important protection against severe cases.
