Daijiworld Media Network - Washington

Washington, Nov 19: The United States may be heading toward a second consecutive severe influenza season, with health experts warning that a mutated flu strain — known as subclade K — is driving early surges in the United Kingdom, Canada, and Japan, and could soon fuel a similar spike across America.

Last year, the US witnessed one of its worst flu seasons in nearly 15 years, marked by exceptionally high hospitalization rates and the tragic loss of at least 280 children, the highest pediatric toll recorded since data reporting began in 2004.

Now, with holiday travel approaching and vaccination numbers dipping, specialists fear that the coming weeks could paint an even grimmer picture.

According to the latest FluView report from the US Centers for Disease Control and Prevention (CDC), flu activity remains low but is rising steadily. Most infections this year are linked to the H3N2 strain of Influenza A, nearly half of which belong to the emerging subclade K variant — the same strain behind a harsher-than-usual flu wave in the Southern Hemisphere earlier this year.

Experts note that this variant was not a significant factor when vaccines were formulated for the current season, raising concerns of reduced vaccine match.

“We’re not expecting a total loss of protection,” explained Dr. Richard Webby of St. Jude Children’s Research Hospital. “But we might see a slight drop in effectiveness if subclade K becomes the dominant virus — and early indicators suggest it will.”

Scientists from the UK Health Security Agency found that subclade K carries seven important genetic mutations, slightly altering the virus’s structure and making it harder for the body’s immune system to recognize.

Despite the mutations, early UK data offers a glimmer of hope. Flu vaccines this year are still providing strong protection for children, cutting the risk of hospitalization or emergency treatment by nearly 75%.

For adults — including senior citizens — the effectiveness is more modest, between 30% and 40%, according to a preprint study released by UK researchers. Scientists caution that these numbers may change as the season progresses.

“Some protection is always better than none,” said Dr. Adam Lauring of the University of Michigan. “And it’s important to remember that multiple strains circulate each season — no one can predict which one they will encounter.”

Worryingly, fewer Americans seem to be rolling up their sleeves this year. New data from IQVIA reveals that retail pharmacies administered nearly 2.2 million fewer flu vaccines between August and October compared to the same period last year.

With subclade K rapidly gaining ground and vaccine uptake dropping, public health experts warn that the combination could push the US into another challenging flu season.