Comparison of immunogenicity of a whole virion and a subunit influenza vaccine in adults.

The immunogenicity and reactogenicity of a whole virus (Merck Sharp & Dohme) and a subunit (Wyeth) influenza A/New Jersey/76 vaccine were compared in a group of 214 normal adult subjects. Both the seroconversion rate and the magnitutde of hemagglutination inhibition antibody response were significantly (P less than 0.01) lower in the recipients of the subunit vaccine, whereas there were no significant differences in local or systemic reactions between the two preparations. On the basis of these data, we question the previous Public Health Service recommendation that one dose of either preparation of the influenza A/New Jersey/76 vaccine is equally efficacious in individuals over 24 years of age.