Overview
- CDC estimates through Dec. 20 put the U.S. toll at at least 7.5 million illnesses, 81,000 hospitalizations and 3,100 deaths, including eight pediatric deaths.
- Hospital admissions for flu roughly doubled week over week to more than 19,000 in the week ending Dec. 20, as most states report high or very high activity.
- Genetic testing shows a mutated H3N2 lineage known as subclade K is driving the vast majority of recent U.S. cases after early waves in the U.K., Japan and Canada.
- This season’s vaccine is a partial mismatch to subclade K but is still expected to reduce severe disease, and antivirals remain effective when started promptly.
- Vaccination and coverage are lagging last year with about 130 million doses distributed, New York recorded a weekly high of 71,000 cases, and hospitals in several regions report growing strain.