Antigenicity and reactogenicity of influenza A/USSR/77 virus vaccine in children--a multicentered evaluation of dosage and safety.

Clinical trials of monovalent A/USSR/77 (H1N1) and trivalent A/USSR/77 (H1N1), A/Texas/77 (H3N2), and B/Hong Kong/72 inactivated influenza virus vaccines were carried out in 358 children and adolescents. Only split-virus vaccines were administered to children younger than 13 years of age. No serious local or systemic reactions were observed among the study participants. Two doses of vaccine containing 7-20 micrograms of the A/USSR/77 (H1N1) viral antigen were required to achieve serum titers of hemagglutinin-inhibiting (HA1) antibody greater than 1:40. However, single doses containing 7-20 micrograms of the A/Texas/77 (H3N2) or B/Hong Kong/72 antigens stimulated serum HAI antibody levels of 1:40.