A study of acute respiratory disease in the community of Port Chalmers. III. Efficacy of influenza virus subunit vaccines in 1973, 1974 and 1975.

An evaluation of the efficacy of influenza virus subunit vaccine was undertaken during a study of acute respiratory disease in the semi-isolated community of Port Chalmers, New Zealand. In 1973, the administration of a vaccine containing A/England/42/72(H3N2) and B/Roma/1/67 stains was found to produce HI antibody titres greater than or equal to 1:40 to the A and B components in 50 percent of 32 subjects. There was no significant NI antibody response to the A component. During an epidemic of A/Port Chalmers/I/73(H3N2) occurring three to four months after vaccination, vaccinees were not protected from clinical infection. Sixty and ninety-nine subjects received vaccine containing A/Port Chalmers/1/73 and B/Hong Kong/8/73 in 1974 and 1975 respectively. In 1974 all 60 subjects received a second dose of vaccine which was shown to have little effect on the distribution of HI antibody titres. The benefits of annual vaccination in this general practice are unclear.