CDC: Seven US States Report High Flu Activity as Season Starts Early in South and West

The CDC's latest weekly surveillance update said seven states reported high flu activity last week, up from two states the week before. The agency also reported that more than 3% of doctors' office visits last week were for flu-like illness, a signal that influenza season is underway. The states with high activity were California, Louisiana, Oregon, South Carolina, Tennessee, Texas and Washington. The surge began in the South and West, with Louisiana seeing the worst activity so far.

The CDC estimated at least 2.6 million illnesses, 36,000 hospitalizations and 2,100 deaths so far this season are tied to flu infections. These are statistical estimates from surveillance data, not confirmed case counts, and they can change as more data arrive. Dr. Anna Durbin of Johns Hopkins University said the flu hospitalization rate in mid-October was the highest seen that early in autumn in more than 15 years. The CDC said early activity is higher than usual, but that does not by itself determine how severe the full season will be.

This season's circulating virus is mostly a mutated version of influenza A H1N1, a strain that can potentially evade some immune defenses. Andrew Pekosz of Johns Hopkins said current data suggest the season's vaccine can recognize the virus and work against it, while noting officials will not know vaccine effectiveness for months. Louisiana has often been among the first states to see flu surges, partly because of lower vaccination rates, higher poverty and health care access barriers, according to Dr. Fred Lopez of LSU Health Sciences Center.

For people in affected regions, the immediate action is vaccination, especially before Thanksgiving travel and gatherings, though those with significant current symptoms should wait until they recover, per guidance cited in the report. The evidence here is observational public-health surveillance: it can show early geographic spread, visit rates and hospitalization trends, but cannot prove vaccine effectiveness or predict final season severity. The next evidence needed is vaccine effectiveness studies using laboratory and hospital data.