Antibody response to immunization with influenza A/USSR/77 (H1N1) virus in young individuals primed or unprimed for A/New Jersey/76 (H1N1) virus

Abstract

SummaryA group of 269 pupils of the Harbour and Transport Training Institute in Rotterdam (group A), aged 13–20 years, and of 109 patients of the Dr Mr Willem van den Bergh Foundation at Noordwijk (group B), aged 11–21 years, were immunized with a whole virus vaccine containing 10, 20, or 40 μg HA of A/USSR/92/77 (H1N1) influenza virus. A booster vaccination was administered 6 weeks later with 20 μg HA of the same virus. Many of the participants had been immunized during the two preceding years with a whole virus vaccine containing A/New Jersey/8/76 (H1N1) (A/NJ/76) virus. The side-effects, mostly of a moderate nature, increased with the dose of virus in the vaccine. In group A side effects were least frequent in the vaccinees who had never received A/NJ/76 vaccine. A single dose of A/USSR/77 vaccine did not produce satisfactory levels of homologous antibodies. After booster immunization with 20 μg HA of A/USSR/77 virus participants showed a higher homologous antibody response in all vaccine-dose groups if they had not been immunized with A/NJ/76 virus in previous years. After primary and especially after booster immunization with A/USSR/77 virus, a very high response against A/NJ/76 virus and adequate levels of A/NJ/76 antibody were found in participants who had been immunized previously with A/NJ/76 virus. Those who had not been immunized with this virus previously showed no or a very low antibody response to A/NJ/76 virus.