Reactogenicity and immunogenicity of bivalent influenza A and monovalent influenza B virus vaccines in high-risk children.

Seventy-nine high-risk children were immunized with either commercial, bivalent, split-product influenza A vaccine or purified hemagglutinin-neuraminidase bivalent influenza A vaccine, and 78 of these subjects were immunized with commercial, monovalent, influenza B split-product vaccine. The reactogenicity of all three vaccines was low, and there were no severe reactions. Twenty-nine subjects who received hemagglutinin-neuraminidase vaccine as their initial dose and commercial split-product vaccine as a booster dose had significantly lower antibody responses to influenza A/New Jersey/76 virus than subjects who received two doses of commercial split-product vaccine. The responses of the two groups to influenza A/Victoria/75 virus were comparable. Twenty-four subjects with malignancy who were receiving chemotherapy were compared with a group of subjects matched for age and vaccine preparation. Patients with cancer had significantly lower antibody responses to A/New Jersey/76 virus than patients without cancer. The ultimate responses of patients with cancer to A/Victoria/75 and B/Hong Kong/72 viruses were comparable to those of other patients, but early responses were lower.