Antigenic Pattern of Strains of Influenza A and B

Influenza A viruses, as revealed by agglutination-inhibition tests with rooster antisera, comprised a graded series of antigenic forms in which precise subgrouping was not possible by the present method. The B strains examined fell into 3 subgroups. The reappearance from time to time of strains closely related to an earlier prototype, necessitates the selection of a group of strains for a polyvalent vaccine which possess broad immunogenic activity. Certain possible deficiencies in the present formula vaccine were mentioned. The recent outbreak of influenza among Eskimos in remote Victoria Island, Canada, in which there was mortality and morbidity approaching the pandemic form of disease, was apparently caused by 2 different viruses which resembled the well-studied PR8 and FM1 strains of influenza A.