Overview
- Canada’s flu season has begun, with test positivity reaching 5.5% in the week ending Nov. 15 and H3N2 identified as the dominant subtype.
- CDC reporting shows low U.S. flu activity so far, with Louisiana at moderate levels and most confirmed infections occurring in children.
- More than half of recent H3N2 cases analyzed in the U.S. fall into the new subclade K, which differs from the strain used in this season’s vaccine.
- A preliminary United Kingdom analysis indicates the current flu shot still offers at least some protection against the subclade K lineage.
- Children’s hospitals in Canada are expanding staffing and reinstating masking and visitor limits, as experts warn that weakened outreach and vaccine skepticism could suppress uptake.