ANTIGENIC PECULIARITIES OF 1957 INFLUENZA VIRUSES AND SEROLOGIC INDEXES OF IMMUNITY AMONG THE POPULATION

Abstract

This investigation was undertaken to determine whether the peculiarities of circulating influenza viruses and the state of anti-influenzal immunity of the population might have contributed to the spread of the influenza pandemic of 1957. Strains of influenza virus isolated during June and July in and about Moscow were used. The antigenic patterns of 15 Russian strains are tabulated and compared with two different Singapore 1957 strains obtained by way of England and the United States. Despite the complexity of these patterns, some classiffication was possible. The hemagglutination tests must be supplemented by other serologic tests in the study of serologic shifts with respect to new strains. The neutralization test in particular was found to be sensitive and informative, since it detected antibodies against certain strains in serums which had no antihemagglutinins for these strains. The most extensive outbreaks of the disease occurred in cities where the titers of antihemagglutinins among the population were the lowest. The assembled data show that changes occurred in the immunity of the population as well as in the characteristics of the viruses as the pandemic developed.