Middle-aged individuals may be in a perpetual state of H3N2 flu susceptibility

Penn Medicine researchers have found that middle-aged individuals—those born in the late 1960s and the 1970s—may be in a perpetual state of H3N2 influenza virus susceptibility because their antibodies bind to H3N2 viruses but fail to prevent infections, according to a new study led by Scott Hensley, an associate professor of microbiology at the Perelman School of Medicine. The paper was published in Nature Communications.

Middle-aged person sick in bed with water bottle in sweater and scarf.


“We found that different aged individuals have different H3N2 flu virus antibody specificities,” Hensley says. “Our studies show that early childhood infections can leave lifelong immunological imprints that affect how individuals respond to antigenically distinct viral strains later in life.”

Most humans are infected with influenza viruses by three to four years of age, and these initial childhood infections can elicit strong, long lasting memory immune responses. H3N2 influenza viruses began circulating in humans in 1968 and have evolved substantially over the past 51 years. Therefore, an individual’s birth year largely predicts which specific type of H3N2 virus they first encountered in childhood.

This story is by Melissa Moody. Read more at Penn Medicine News.