Effect of dose on antibody response to subunit influenza vaccine.

In a group of third-year medical students who were given subunit influenza virus vaccine, the haemagglutination-inhibition (HI) antibody response to A/Victoria/3/75, and the boosting of HI antibody to previously circulating A strains of the Hong Kong subtype were independent of the dosage in the tested range. There was minimal boosting of antibody levels to the Asian strains which circulated during the childhood of the volunteers. The antibody responses to the B/Hong Kong/8/73 component were lower and were dose-related. There was no appreciable increase in the HI geometric mean titre to any of the strains after a second dose.