Studies with inactivated influenza vaccines purified by zonal centrifugation. 1. Adverse reactions and serological responses.

High (3000 CCA units) and standard low (300 CCA units) doses of formalin-inactivated influenza vaccines purified by zonal ultracentrifugation were evaluated in a double-blind manner for adverse reactions and antibody responses in a high school population and in 2 adult populations.The fewest local and systemic reactions were produced by subcutaneous administration of the low doses of purified monovalent A2/Aichi/2/68, A2/Japan/170/62, and B/Massachusetts/3/66 vaccines. The high doses of A2/Japan and A2/Aichi vaccines produced 2-3-fold greater incidence of adverse reactions but did not exceed that observed with the commercial vaccines. The 3000 CCA units of B/Mass. vaccine produced more frequent and more severe systemic reactions than the polyvalent vaccine.Neither the A2/Japan vaccine nor the commercial vaccines stimulated a significant serum antibody response to A2/Aichi.The homologous serum antibody response to an Aichi vaccine was excellent in all 3 populations. A2/Aichi vaccines produced higher heterologous A2/Japan titres than did the A2/Japan vaccines. It was demonstrated that high doses of purified influenza vaccine can be given safely, and that 10-fold increases in vaccine concentration produce 2-3-fold increases in antibody titre.