Laboratory Studies on the 1950 Outbreak of Influenza

Abstract

Four strains of influenza virus isolated from 3 outbreaks early in 1950 were shown to be influenza A strains. Studies on the antigenic relationships of current and previously isolated strains of virus by the serum neutralization and agglutination-inhibition technics with rooster and ferret antisera revealed differences which suggested progressive and continuous change in antigenic composition. The 1950 strains were essentially identical but differed antigenically from the 1947 (FM1) virus. The significance of these changes in antigenic composition in relation to prophylactic immunization in man is discussed.