Mutated H1N1 Pushes US Flu Season 2.5 Months Early as West Coast Hits 10% Positivity
Updated
Updated · CNN · Oct 23
Mutated H1N1 Pushes US Flu Season 2.5 Months Early as West Coast Hits 10% Positivity
3 articles · Updated · CNN · Oct 23
Summary
Washington state recorded flu positivity near 10% last week, a level experts said resembles January rather than late October as the US season starts unusually early on the West Coast.
H1N1 accounts for about 98% of samples in one Seattle lab, and a G155E mutation appears to help the virus evade existing immunity, driving spread eastward after an early wave from Asia.
CDC data still show influenza-like illness at 2.1% of doctor visits nationwide—below the national baseline—though Pacific states have already reached significant activity and the South is rising quickly.
This year's vaccine was selected before the mutation emerged, so experts say shots should still help but may be less well matched; they urged people to get vaccinated immediately rather than wait until Halloween.
The early surge is also renewing pressure for faster vaccine production, with specialists pointing to mRNA shots as a potential alternative to slower, cheaper egg-based manufacturing and warning a second flu wave could follow in winter.