Clinical trials of monovalent influenza A/New Jersey/76 virus vaccines in adults: reactogenicity, antibody response, and antibody persistence.

Responses to monovalent influenza A/New Jersey/76 virus vaccines were evaluated in 22-43-year-old, antibody-negative males. Three doses of vaccine (200, 400, and 800 chick cell-agglutinating [CCA] units) from each of four manufacturers and a placebo were given intramuscularly. Mild systemic complaints occurred in 12% of vaccines and moderate reactions in 5%, mostly in recipients of 800 CCA units of the vaccines. Reactogenicities of subvirion vaccines were intermediate, while different preparations of whole-virus vaccine were the most and the least reactogenic. Local reactions to 200-CCA unit doses of vaccines resembled reactions to placebo. Serum antibody responses against influenza A/swine/37 virus and current swine-like strains were similar for recipients of vaccines from three manufacturers. Among recipients of 200 CCA units of the vaccines, 79% developed antibody titers of greater than or equal to 1:20. Increasing antibody response was not uniformly associated with increasing vaccine dose but did correlate with increasing reactogenicity. Antibody titers fell about twofold over six months, and they fell slightly more for recipients of subvirion than for recipients of whole-virus vaccines.