Flu Season Forecast: New Variant Raises Concerns for Winter 2023

Flu season could be particularly severe this winter, according to early data from health experts. Richard Webby, a flu researcher at St. Jude Children's Research Hospital, notes that the indications suggest a potentially impactful season.

He points to the Southern Hemisphere's flu activity, which often serves as a precursor for the Northern Hemisphere's trends. This past winter, the Southern Hemisphere saw prolonged flu activity, a situation that could mirror what the U.S. experiences.

The Centers for Disease Control and Prevention reports that the dominant flu strain currently in circulation is the H3N2 virus. Webby highlights that H3N2 seasons tend to result in higher levels of severe illness.

The last significant flu season driven by the H3N2 strain was in 2016-2017. Adding to the complexity, a new variant of H3N2 has emerged, which epidemiologist Caitlin Rivers from Johns Hopkins describes as sufficiently distinct from prior strains.

This mutation may allow the virus to evade some of the immune protections provided by previous infections or vaccinations. Rivers also cautions that the flu vaccine this year may not be as effective against this new variant.

However, data from the United Kingdom suggests that the vaccine still offers a protective benefit, showing around seventy to seventy-five percent effectiveness against hospitalization in children and thirty to forty percent in adults.

With flu activity on the rise, Rivers urges individuals who have not yet received their flu shot to do so immediately, as it takes about two weeks for immunity to develop. She emphasizes the importance of getting vaccinated before the peak flu season, which typically occurs around the holiday timeframe.

Each winter, the flu claims between twelve thousand and fifty-two thousand lives in the U.S. Rivers expresses concern that vaccination rates for both flu and COVID-19 may decline this year, citing damaging rhetoric regarding vaccine safety and effectiveness from some federal officials.

In a statement to NPR, a spokesperson from the Department of Health and Human Services acknowledged the uncertainty surrounding the viruses that will circulate this season and emphasized that vaccination is a personal choice that should be discussed with healthcare providers.