Preventing seasonal sniffles may be more complicated than researchers suspected. A vaccine that protects piglets from one common influenza virus also makes them more vulnerable to a rarer flu strain, researchers report today in Science Translational Medicine1.
The team gave piglets a vaccine against H1N2 influenza. The animals responded by making antibodies that blocked that virus — but aided infection with the swine flu H1N1, which caused a pandemic among humans in 2009. In the study, H1N1 infected more cells and caused more severe pneumonia in vaccinated piglets than unvaccinated ones.