Abstract
BACKGROUND: A primary reason for non-adherence to malaria chemoprophylaxis is fear of latent side effects. We examined latent effects of malaria chemoprophylaxis among Returned Peace Corps Volunteers (RPCVs). METHODS: During July 18-September 16, 2016, RPCVs who served during 1995-2014 with an e-mail address in Peace Corps' RPCV database were invited to take an internet-based survey on malaria prophylaxis and medical diagnoses. "Good adherence" meant taking prophylaxis "as prescribed" or "most of the time." Prevalence of diseases diagnosed after Peace Corps service was compared between users and nonusers of each antimalarial using log-binomial regression. RESULTS: Of 8931 participants (11% response rate), 5055 (57%) took chemoprophylaxis. Initial chemoprophylaxis was mefloquine 59%, chloroquine 13%, doxycycline 16%, atovaquone-proguanil 4%, and "other" 8%. Sixty percent reported good adherence. Mefloquine users had the best adherence (67% good adherence). Prevalences of most diseases were similar between exposed and unexposed groups. Certain psychiatric diagnoses were slightly more likely among mefloquine users (PR 1.14, 95% CI [1.04-1.25], P = 0.0048). When excluding those with prior psychiatric illness, there were no differences in psychiatric diagnosis rates. CONCLUSION: Malaria chemoprophylaxis use by Peace Corps Volunteers is safe. Avoiding mefloquine use in those with prior psychiatric illness can reduce psychiatric side effects.