The U.S. avoided a long-feared "twindemic" of flu and COVID-19 for the past two years, largely because of widespread masking and other behaviors that kept flu seasons mild. But the risk that both illnesses will increase this winter appears greater.
"This could very well be the year in which we see a twindemic," William Schaffner, MD, infectious disease professor at Nashville, Tenn.-based Vanderbilt University, told NPR in a Sept. 23 report. "That is, we have a surge in COVID and simultaneously an increase in influenza. We could have them both affecting our population at the same time."
Experts believe the risk is greater this year because widespread masking and other prevention measures are no longer commonplace, and there are already signs that this year's upcoming flu season will be more severe, based on the Southern Hemisphere's severe flu season, which typically runs from April to September.
Flu trends in the Southern Hemisphere offer health experts strong indications of what could be in store for the U.S., and Australia is coming out of its worst flu season in five years. HHS data compiled by The New York Times shows about 35,000 people in the U.S. are still hospitalized with COVID-19 every day, and the CDC estimates flu causes between 140,000 and 710,000 hospitalizations annually. Pediatricians in Southern California are already seeing an uptick of flu cases among children.
"We should be worried," Richard Webby, PhD, an infectious disease specialist at Memphis, Tenn.-based St. Jude Children's Research Hospital, told NPR. "I don't necessarily think it's run-for-the-hills worried. But we need to be worried."
Viral interference — a biological phenomenon in which infection with one respiratory illness reduces the risk of catching another — may offset the twindemic threat. But "the best prevention tool we have" are flu vaccines, experts say.