Comparison of the safety, tolerability, and immunogenicity of a MF59-adjuvanted influenza vaccine and a non-adjuvanted influenza vaccine in non-elderly adults

The adjuvanted influenza vaccine FLUAD(TM) is composed of subunit influenza antigens combined with the MF59-adjuvant emulsion. The vaccine was developed primarily for use in elderly populations, but non-elderly individuals might also benefit. To evaluate this hypothesis, 301 healthy adults were assigned randomly to receive two intramuscular injections of either FLUAD(TM) (150 subjects) or a non-adjuvanted vaccine, Fluzone(TM) (151 subjects), in two trials conducted at a 1-year interval. Injections consisted of 15 mug per 0.5 ml dose. Vaccine composition was A/Texas/36/91 (H1N1), A/Johannesburg/33/94 (H3N2), and B/Harbin/7/94 for the first injection and A/Texas/36/91 (H1N1), A/Nanchang/933/95 (H3N2), and B/Harbin/7/94 for the second injection. Immunogenicity was evaluated at 28 and 180 days post-immunization. FLUAD(TM) was generally well tolerated in healthy adults when compared with Fluzone(TM). FLUAD(TM) was associated with increased pain at the injection site after immunization. A statistically significant increase in the incidence of injection-site warmth, chills, myalgia, and analgesic/antipyretic use occurred in the FLUAD(TM) group after the first injection but not after the second injection. In both groups, most of these local and systemic reactions were classified as mild. FLUAD(TM) was more immunogenic than Fluzone TM following both injections. After the first injection, statistically significant differences were found in the percentage of subjects with four-fold rises in hemagglutinin inhibition (III) titers at 28 days post-immunization for the B antigen. After the second injection, the FLUADTM group had significantly higher HI titers, a significantly higher percentage with a four-fold increase in titer, and a significantly greater percentage of subjects with titers greater than or equal to 160 for the H3N2 antigen at 28 days. Only minor immunogenicity differences between the two groups were seen at 180 days. Compared with Fluzone(TM), FLUAD(TM) was associated with increased immunogenicity and mild post-immunization reactions in healthy adults. The magnitude of increased immunogenicity in healthy adults was less than that seen in elderly populations. (C) 2003 Elsevier Ltd. All rights reserved.