Prior exposure to one strain of influenza virus may weaken children’s ability to mount an effective antibody response against their subsequent exposure to a different flu strain, according to a study led by Weill Cornell Medicine investigators. The analysis of the pediatric response to H3N2 and H1N1 influenza A viruses, two of the most common causes of flu, provides insight into the concept of “immune imprinting,” and supports the idea that childhood vaccination, if properly designed, may be able to mitigate its adverse effects.
Immune imprinting, first described in 1960, refers to a long-term bias or skew in the immune response that a first viral exposure can introduce, with potentially serious impairment of subsequent responses to closely related viruses. Imprinting has been difficult to research and is far from being well understood. However, in the study, published March 11 in Nature, the researchers were able to analyze antibodies from participants, including children 2 to 6 years old who had their sequential first exposures to the two types of influenza A viruses circulating in humans. They determined that following an initial H3N2 exposure, antibodies generated that could bind both H3N2 and H1N1 were ineffective at stopping most H1N1 strains.
