Flu activity rises early as new mRNA vaccine receives FDA approval

U.S. health agencies report that influenza activity is climbing earlier than usual, with case levels in October comparable to those typically seen in December or January. The Centers for Disease Control and Prevention said the early-season activity is higher than normally observed, though most of the country remains in a minimal range of flu cases.

The early surge was first detected in western states, including California, Washington, Hawaii and Alaska, before spreading to other regions. Experts suggest the pattern could reflect changes in the circulating virus.

In response to the evolving situation, the Food and Drug Administration approved mFLUSIVA in August, marking the first mRNA flu vaccine for adults aged 50 and older. Unlike conventional flu shots, the vaccine uses messenger RNA to instruct immune cells to target the flu virus, employing the same technology used in COVID-19 vaccines.

"There is some evidence that suggests mFLUSIVA may offer somewhat better protection against the flu than traditional flu vaccines," said Dr. Rebecca Choudhury, an infectious disease specialist at Mount Sinai.

Clinical data indicated a 27% lower infection rate among adults 50 and older who received the mRNA vaccine compared with those who received traditional vaccines, with rare adverse reactions similar to those of standard shots. Dr. Choudhury recommended the new vaccine for adults 50 to 64, especially those with chronic health conditions, but advised that the traditional flu shot remains a viable option when the mRNA vaccine is unavailable.

The CDC continues to recommend annual flu vaccination for everyone six months and older. This year’s standard flu vaccines target three strains: H1N1, H3N2, and influenza B, with H1N1 accounting for more than 75% of positive tests in the past month.