A sort of influenza “Achilles heel” has been discovered that makes those born in the late 1960s and 1970s more vulnerable to the disease. According to a study by the University of Pennsylvania , in the United States, it is a state of susceptibility to the H3N2 virus  due to antibodies: they are able to bind to the pathogen, but are unable to prevent its infections.

In a study published in the journal Nature Communications , researchers demonstrated this substantial difference in the immune system.

Coronavirus-might-have-been-infecting-humans-as-early-as-October-2019

Footprint of childhood infections – “We found that individuals of different ages have different antibody specificities against the H3N2 influenza virus,” explained Scott Hensley, the microbiology professor who led the work. “Our studies show that early childhood infections can leave lifelong immunological footprints that affect how individuals respond to antigenically distinct viral strains later in life.”

Circulating viruses in 1968 – Most humans, the researchers noted, become infected with influenza viruses between the ages of three and four, and these infections can elicit strong and lasting immune responses. The H3N2 influenza viruses began to circulate in 1968 and have evolved over the years. To arrive at these conclusions, the researchers compared the levels of antibodies of children and adults and noted that children aged three to ten had higher levels of neutralizing antibodies against contemporary H3N2 viruses. Most of those born in the 1960s and 1970s had antibodies that could bind to viruses but could not prevent viral infections.