Comparison of the hemagglutination-inhibiting and neutralizing antibody responses of volunteers given 400 chick cell-agglutinating units of influenza A/New Jersey/76 split-virus vaccine.

Thirty-two volunteers 25 years of age or older who were employees of the Laboratory of Infectious Diseases (National Institute of Allergy and Infectious Diseases, Bethesda, Md.) were given 400 chick cell-agglutinating units of influenza A/New Jersey/76 virus vaccine (Wyeth Laboratories, Philadelphia, Pa.) intramuscularly. Sera were assayed for hemagglutination-inhibiting (HAI) and neutralizing antibody before and after inoculation. All 32 subjects had a fourfold rise in titer of HAI antibody, and 25 of 32 had a similar rise in titer of neutralizing antibody. The average log2 rise was 4.5 for HAI antibody and 4.1 for neutralizing antibody. Therefore, this vaccine is believed to be capable of stimulating HAI and neutralizing antibodies to an equal extent.