vol21no7_pdf-version

RESEARCHTable 1. Description of studies included in analysis of hepatitis virus seroprevalence, Malawi, 1989–2008*Study name,period (reference) Study site/setting Study typeStudypopulationHIVstatusAims of studyICAR,1989–1994(21,22)Queen Elizabeth CentralHospital, Blantyre/urbanObservationalcohortPregnant andpostpartum+/– Assess adverse pregnancy outcomes andrates of mother-to-child transmission ofSUCOMA, 1998(23)NVAZ, 2000–2004(24)MWANZA, 2001(T.E. Taha, unpub.data)METRO, 2003–2005 (25)PEPI, 2004–2008(26)Nchalo District, sugarestate/rural, occupationalQueen Elizabeth CentralHospital, Blantyre/urbanMwanza District/ruralQueen Elizabeth CentralHospital; health centers inBlantyre/urbanQueen Elizabeth CentralHospital; health centers inBlantyre/urbanObservationalsurveyRandomizedclinical trialObservationalsurveyRandomizedclinical trialRandomizedclinical trialwomenHIVAdult men +/– Identify epidemiologic and biologicdeterminants of HIV infection in anoccupational male cohortPregnantwomenAdult men andwomenAdult women(nonpregnant)Pregnantwomen+ Assess efficacy of short antiretroviralpost-exposure prophylaxis to preventmother to child transmission of HIV+/– Assess risk factors associated withprevalent HIV infection in a rural areaadjacent to the borders with Mozambique+/– Assess the efficacy of intermittentintravaginal metronidazole gel use inreducing bacterial vaginosis infection+ Assess efficacy of extended antiretroviralpostexposure prophylaxis to preventmother to child transmission of HIV*ICAR, International Collaborations on AIDS Research; SUCOMA, a study of HIV prevalence among male workers for the Sugar Company of Malawi;NVAZ, a study of efficacy of nevirapine/zidovudinel postexposure prophylaxis to prevent mother-to-child transmission of HIV; MWANZA, a study of riskfactors associated with prevalent HIV infection in the rural town of Malawi; METRO, a study in which efficacy of intravaginal metronidazole gel in reducingbacterial vaginosis was assessed; PEPI, a study of antiretroviral postexposure prophylaxis to prevent mother to child transmission of HIV.regression to estimate adjusted odds ratios. Because of differencesin follow-up periods and inconsistencies in availabilityof comparable data, we used baseline data for allcovariates, regardless of whether an enrollment or followupsample was used for the hepatitis testing. A p value of≤0.05 was considered statistically significant. Analysis wasperformed by using Stata version 11.2 (StataCorp LLC,College Station, TX, USA).Previous data on the prevalence of hepatitis E in Malawiwas not available. To estimate an appropriate samplesize for this analysis, a conservative prediction of 2%prevalence was used. A sample size of 800 was determinedto enable detection of a prevalence of 2% with aprecision of 1% (28).ResultsTable 2 shows the distribution of hepatitis seropositivityoverall and across main exposure variables. Overall,132 (16.5%) of 800 samples tested positive for HEV antibodies.The overall seroprevalence of HAV antibodies,HBsAg and HCV antibodies in samples collected fromdifferent populations in Malawi was 99.6%, 7.5%, and7.1%, respectively (Table 2). HEV seroprevalence washigher among HIV-uninfected (20.2%) than among HIVinfected(12.9%) persons, and HCV seroprevalence washigher among male (10.2%) than female (5.6%) (p