Hepatitis E in Bangladesh: Insights from a National Serosurvey.

BACKGROUND Hepatitis E virus, typically genotypes 1 and 2, is a major cause of avoidable morbidity and mortality in South Asia. Although case fatality risk among pregnant women can reach as high as 25%, a lack of population-level disease burden data has been cited as a primary factor in key global policy recommendations against the routine use of licensed hepatitis E vaccines, one of the only effective tools available for preventing disease and death. METHODS We tested serum from a nationally-representative serosurvey in Bangladesh for anti-HEV IgG. We estimated the proportion of the population with evidence of historical HEV infection and used Bayesian geostatistical models to generate high-resolution national maps of seropositivity. We examined variability in seropositivity by individual-level, household-level, and community-level risk factors using spatial logistic regression. RESULTS We tested serum samples from 2924 individuals from 70 communities representing all divisions of Bangladesh and estimated a national seroprevalence of hepatitis E of 20% (95% CI 17-24%). Seropositivity increased with age and male sex (Odds Ratio: 2.2 male vs. female, 95% Confidence Interval: 1.8-2.8). Community-level seroprevalence ranged from 0-78% with the seroprevalence in urban areas being higher, including Dhaka, the capital, with 3.0-fold (95% Credible Interval 2.3-3.7) higher seroprevalence than the rest of the country. CONCLUSION Hepatitis E infections are common throughout Bangladesh. Strengthening clinical surveillance for hepatitis E, especially in urban areas may help generate additional evidence needed to appropriately target interventions like vaccines to the populations most likely to benefit.