Finding Viruses Hidden in Plain Sight

Throughout the COVID-19 pandemic, we’ve heard about rising numbers of cases. But assessing a population’s exposure to a virus is difficult because existing methods may not account for multiple circulating strains, rates of vaccination, and levels of natural immunity. Recognizing this, researchers in Vietnam tested 24,402 serum samples collected between 2009 and 2015 for antibodies against 11 human influenza A strains (1). After obtaining a composite antibody measurement, they found that 26 percent of the Vietnamese population is exposed to H3N2 influenza every year and 16 percent is exposed to H1N1 – higher than expected in temperate countries.

“Our study population had almost zero influenza vaccination, so we were able to use our antibody measurements as true indicators of past influenza infection,” said co-lead author Maciej F. Boni (2). “But we still need a better understanding of how to distinguish infected individuals from vaccinated individuals, and how to include the effects of antibody waning into an analysis like this.”