A double-blind randomized study with bivalent influenza virus vaccines was conducted to compare the local and systemic reactions and immunogenicity of a whole-virus vaccine and a split-product vaccine in children. Fevers of greater than 100 F were more frequent after vaccination with whole-virus than split-product vaccine especially in children one to four years old (69% vs 22%; P less than 0.01). Fevers of greater than or equal to 103 F did not occur in children who previously had been given influenza virus vaccine, even in the absence of preexisting homologous serum antibody. The immune response to the A/Port Chalmers/1/73 antigen in the vaccine was similar after administration of either whole-virus or split-product vaccine. However, split-product vaccine induced significantly less hemagglutination-inhibiting antibody to B/Hong Kong/5/72 virus in children younger than 10 years who had not been previously immunized; only 43% developed detectable antibody vs. 100% of those vaccinated with whole virus vaccine (P less than 0.01). These studies indicate that (1) in young children whole-virus vaccine causes fever more frequently than split-product vaccine; (2) young children previously vaccinated with influenza virus vaccine are unlikely to experience fever subsequent to immunization with a related antigen; and (3) split-product vaccine induces less antibody to B/Hong Kong/5/72 virus than whole-virus vaccine in immunologically unprimed young children.

Healthy ambulatory elderly were immunized with increasing doses of the 1984-1985 influenza vaccine formulation. Two types of vaccines, split-product vaccine (SPV) and whole virus vaccine (WVV), were used. Three different doses, 0.5 mL (the standard volume, 1X), or 1.0 mL (2X), and 1.5 mL (3X) of each of the two vaccines were compared. The size of each of the six groups was between 23 and 26 subjects. The mean ages in each of the groups ranged from 71 to 74 years. No difference in local or systemic reaction was noted among the six groups. A dose-response effect was observed for the SPV recipients to the influenza A/Chile/83 (H1N1) strain. The geometric mean hemagglutination inhibition (HI)titer (GMT) was 1:76 after the 3X dose vs 1:38 after the 1X dose (P less than 0.025). To the influenza A/Philippines/82 (H3N2) strain the GMT was 1:70 after the 3X dose vs 1:43 after the 1X dose. A similar trend was noted for the influenza B/USSR/83 strain. A (HI) titer of greater than or equal to 1:40 for all the strains was seen in greater than 70% of the split product vaccine recipients only after the 3X dose. For the WVV recipients, increasing doses did not result in increasing GMT for any of the three vaccine strains. In addition, HI titers greater than or equal to 1:40 were not uniformly seen in greater than 70% of the vaccine recipients at any of the three whole virus vaccine doses.(ABSTRACT TRUNCATED AT 250 WORDS)

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