Serologic responses and systemic reactions in adults after vaccination with monovalent A/USSR/77 and trivalent A/USSR/77, A/Texas/77, B/Hong Kong/72 influenza vaccines.

Four hundred twenty-six volunteers aged 16 to 83 years were given experimental doses of inactivated monovalent [A/USSR/77 (H1N1)] and trivalent [A/USSR/77 (H1N1), A/Texas/77 (H3N2), B/Hong Kong/72] influenza vaccines as part of a double-blinded, placebo-controlled, national collaborative study. Local reactions at inoculation sites occurred in less than 6.6% of volunteers. Systemic reactions, generally consisting of low-grade fever, myalgia, or headache, lasting less than 24 hr, did not occur more frequently in vaccinees than in placebo recipients. Vaccines containing lower doses of the A/Texas/77 (H3N2) hemagglutinin (8-10 micrograms) and B/Hong Kong/72 hemagglutinin (6-9 micrograms) produced hemagglutinin-inhibiting (HAI) antibody responses equivalent to those produced by higher doses (15-28 and 19-28 micrograms, respectively) in all age groups. Single injections of vaccines containing lower doses of A/USSR/77 (H1N1) hemagglutinin (4-7 micrograms) induced titers of HAI antibody of greater than 1:40 in 93% of volunteers greater than or equal to 26 years of age but in only 58% of volunteers less than 26 years of age. In this latter group, two injections containing higher doses (10-19 micrograms) induced better antibody responses. Vaccines containing approximately 6-15 micrograms of hemagglutinin of each antigen can be expected to be well tolerated and to induce good HAI antibody responses in a one- or two-dose regimen, depending on the age group.