A Cochrane review «Antibiotic prophylaxis for leptospirosis»1 «Brett-Major DM, Lipnick RJ. Antibiotic prophylaxis for leptospirosis. Cochrane Database Syst Rev 2009 Jul 8;(3):CD007342. »1 included 3 studies with a total of 1 828 subjects. One trial assessed post-exposure prophylaxis in an indigenous population after a flood without apparent efficacy in reduction of clinical or laboratory identified Leptospira infection. Two trials assessed pre-exposure prophylaxis, one among deployed soldiers and another in an indigenous population. Despite an OR of 0.05 (95% CI 0.01 to 0.36) for laboratory-identified infection among deployed soldiers on doxycyline in one of these two trials, pooled data showed no statistically significant reduction in Leptospira infection among participants (Odds ratio 0.28 (95% CI 0.01 to 7.48). Minor adverse events (predominantly nausea and vomiting) were more common among those on doxycycline with an odds ratio of 11 (95% CI 2.1 to 60).
Comment: The evidence is downgraded by study quality (inadequate or unclear allocation concealment and lack of intention-to-treat analysis).