Correlation of laboratory studies with clinical responses to A/New Jersey influenza vaccines

The large, uniformly performed clinical investigations with influenza A/New Jersey vaccines provided an opportunity to correlate results of laboratory tests of vaccine with human reactivity and antibody responses. These vaccines were given to large numbers of subjects under code, and significant differences in immunogenicity and reactivity were observed in unprimed individuals. A single, relatively large dose of intact virus was more immunogenic and reactive than split-virus vaccines in unprimed subjects. Differences in immunogenicity and reactivity in unprimed subjects correlated with the amount of intact virus in the vaccines (measured by column chromatography or electron microscopy) and with the amount of viral hemagglutinin in the vaccine (measured by immunodiffusion), but not with the number of chick cell-agglutinating units.