Antibody Response in Man to Hong Kong Influenza Following 1967 Formula Influenza Vaccine in Adjuvant 65

Abstract
Summary The development of adjuvant 65 has added a new dimension to the prospects for the control of influenza by vaccine. Previous studies with the adjuvant revealed heightened antibody response of long duration, employing a reduced amount of antigen, and broadening of the antigenic coverage between heterologous strains within a single subtype, e.g., Asian. The present study revealed a broadening of antigenic coverage to cross the barriers of major antigenic change as revealed by the stimulation of antibody against Hong Kong virus in 55% of 67 persons given 2 doses of 1967 formula polyvalent influenza vaccine in adjuvant. Such antibody might have provided substantial protection against the morbidity and mortality of Hong Kong virus before the new vaccine was available and might also have contributed to limitation of spread of the virus. Only 1 of 71 persons given the corresponding aqueous vaccine developed such antibody. There was a striking deficiency in antibody against Hong Kong virus in the sera of persons collected prior to the emergence of the virus. However, antibody was occasionally seen in persons as young as 13 years and there was generally an increase in seropositive persons with age. This appeared to be related to development of composite immunity against influenza virus strains by repeated experience with these agents rather than to previous experience with an antigenically similar virus.