EFFICACY OF ANTIBIOTIC-PROPHYLAXIS FOR PREVENTION OF LYME-DISEASE

OBJECTIVE: To determine if antibiotic prophylaxis following a deer tic k bite is effective in reducing the risk of developing Lyme disease. D ESIGN: Meta-analysis of published trials. DATA IDENTIFICATION: Clinica l trials were identified by a computerized literature search of MEDLIN E and by an assessment of the bibliographies of published studies. STU DY SELECTION: Trials were included in the analysis if their patients w ere randomly allocated to a treatment or control group, enrolled withi n 72 hours following an Ixodes tick bite, and had no clinical evidence of Lyme disease at enrollment. Three trials were selected for review after inclusion criteria were applied. DATA EXTRACTION: Data were extr acted for details of study design, patient characteristics, interventi ons, duration of therapy, and number of adverse events in each arm of therapy. RESULTS OF DATA SYNTHESIS: Among the 600 patients with Ixodes tick bites, the rate of infection in the placebo group was 1.4%. In c ontrast, patients who received antibiotic prophylaxis had a 0% infecti on rate. The pooled odds ratio, comparing prophylaxis to placebo, was 0.0 (95% confidence interval 0.0, 1.5) (p = .12). CONCLUSIONS: The ava ilable evidence to date suggests that the routine use of antibiotic pr ophylaxis for the prevention of Lyme disease remains uncertain. Mete-a nalysis of the controlled trials failed to establish definitive treatm ent efficacy owing to the small sample size of the combined trials and the low rates of infection following a deer tick bite, A larger rando mized trial is needed to demonstrate definitively that prophylaxis is more effective than placebo in reducing the risk of early Lyme disease in endemic areas.