Lyme disease is a potentially serious infection which is caused by the spirochaete Borrelia burgdorferi and is endemic in certain areas of North America, Europe and Asia. Lyme disease vaccine (LYMErix) is an adjuvanted formulation of the outer surface protein A (OspA) of the causative spirochaete. It acts by inducing high titres of anti-OspA antibodies (anti-OspA), which must be present in vaccinated individuals before exposure to B. burgdorferi to provide protection against Lyme disease. Lyme disease vaccine efficacy against Lyme disease was 80% for definite and asymptomatic cases and 76% for definite cases at year 2 using the recommended dosage regimen [30 microg at months 0, 1 and 12 (0, 1, 12 schedule)] in a randomised, double-blind, multicentre trial in 10,936 enrolled adult volunteers who resided in areas of the US endemic for Lyme disease. On the basis of an anti-OspA correlate of protection, Lyme disease vaccine 30 microg was equally effective when administered by a shorter schedule (0, 1, 6 schedule); > or = 90% of adult volunteers developed protective anti-OspA titres with this or the 0, 1, 12 schedule. Although published data are fewer, a 0, 1, 2 schedule has also shown promise in adults. In addition, virtually all children (aged 2 to 15 years) given Lyme disease vaccine 30 microg developed protective anti-OspA titres, but published data are also limited and results of a large paediatric trial are awaited with interest. Long term protection against Lyme disease appears to be possible with Lyme disease vaccine. Although anti-OspA titres decline rapidly after completion of the recommended schedule, booster doses of 30 microg of the vaccine induced protective anti-OspA titres in > or = 96% of adult volunteers when administered 12 and/or 24 months later. Lyme disease vaccine 30 microg is well tolerated: most vaccination-related adverse events were transient and mild or moderate in severity in clinical trials. The most common spontaneously reported adverse event was pain at the injection site in 24% of vaccine recipients (vs 7.6% of the placebo group). The incidence of spontaneously reported, early nonspecific systemic adverse events was <4% but was higher with the vaccine than with placebo for some events (e.g. myalgias, fever and chills but not arthralgia). There appeared to be no association between the vaccine and the incidence of arthritis or any late systemic adverse events. The tolerability profile of Lyme disease vaccine did not appear to vary with the schedule of administration, nor to differ between adults and children.
Conclusions: Lyme disease vaccine, an adjuvanted formulation of OspA, protects most adults against Lyme disease when administered by the recommended 0, 1, 12 schedule before disease exposure, and is well tolerated. The optimal schedule(s) of administration, duration of protection against Lyme disease, long term tolerability in adults and potential role in children are not fully defined for this vaccine. Lyme disease vaccine is indicated in North America for active immunisation of adults at moderate to high risk of contracting Lyme disease.