Vaccination of infants and schoolchildren with an influenza subunit vaccine (author's transl)

A new influenza subunit vaccine which contains only hemagglutinin and neuraminidase antigens was investigated for reactogenicity and immunogenicity in children aged between three and 15 years. Children under six years of age received either 500 IU or 1000 IU of the commercial vaccine, those aged from six to 15 years either 1000 IU or 2000 IU. The vaccines contained the virus strains recommended by the World Health Organisation for the vaccination season 1976/77. In a double blind study the vaccinees were allocated at random to the different dosage groups. The children were examined for reactions by the vaccinating physician 24 hours after vaccination. Serum hemagglutination inhibiting antibody titers were determined before vaccination and four weeks after vaccination. In the younger age-group additional antibody determination was made two weeks after a booster injection. A very low rate of side-reactions was observed in all dosage groups. The increase of the antigen content was not associated with a higher rate of side reactions. After the first vaccination a significant rise of antibody titers could be observed in all children. After the booster injection a further increase of these antibody titers was observed. The response of the younger age group to the dosages 500 and 100 IU did not different significantly. In contrast, in the older age group the increase of the dosage from 1000 to 2000 IU was connected with a better immune response. This was especially marked in the antibody titers against the influenza B-strain virus.