Objective: To evaluate the safety and immunogenicity of a recombinant outer surface lipoprotein A (OspA) Lyme vaccine in healthy adults.
Design: Randomized, double-blind, placebo-controlled trial.
Setting: Clinical research unit of a medical center.
Participants: Thirty-six healthy adult volunteers aged 18 through 65 years.
Interventions: Volunteers were randomly assigned to receive two 10-micrograms doses of OspA Lyme vaccine, OspA Lyme vaccine adsorbed to alum, or a buffer placebo. Subjects in the OspA Lyme vaccine group received a third dose. Patients were assessed after each vaccination for a total follow-up period of 1 year. Serum samples for antibody determination were drawn at baseline, 2 and 3 weeks after dose 1, once per week for 4 weeks after dose 2, 20 weeks after dose 2, and 1 month after dose 3.
Main outcome measures: Local and systemic adverse reactions and antibody levels specific for OspA.
Results: The most common reactions were local pain and tenderness at the injection site. Adverse events did not increase following the second or third dose. Two doses of both vaccine formulations elicited high-titer antibodies that inhibited replication of Borrelia burgdorferi in vitro. No differences were noted in antibody levels elicited by the adsorbed and nonadsorbed formulations.
Conclusion: Two or three doses of OspA Lyme vaccine are safe and immunogenic in adults.