Hepatitis E: Determinants of Severe Symptomatic Disease in Displaced Populations of South Sudan
Hepatitis E virus (HEV) has over the last three decades emerged as a cause of outbreaks in displaced populations. Effective deployment of an HEV intervention toolkit that includes HEV vaccines requires epidemiological characterization of HEV trends in vulnerable populations. The study purpose is to describe the epidemiology of HEV and identify factors for severe HEV disease in displaced populations of South Sudan. The agent-host-environment model was used. A nested retrospective cohort study was used with a sample of 14,404 cases for the descriptive case-series and 4,810 cases for the retrospective cohort. Data analyses included cumulative incidence and mortality rates, SatScanï space-time analysis, correlation and simple linear regression, odds ratio, and logistic regression. Sustained HEV transmission occurred from 2012 to 2017 with rising transmission in the rainy season but no significant correlation between precipitation and HEV cases. The median outbreak duration was 1 year 11 months. The outbreaks were attributed to HEV genotype 1 subtype 1e with the risk of HEV disease and death (as cases and deaths per 10,000) being higher in males (591 versus (vs) 23), adults (18-59 years) (367 vs 14), and elderly (60+ years) (353 vs 22). The factors associated with severe HEV disease include (a) altered mental status (adjusted Odds Ratio [aOR] = 640.24, 95% CI: 209.35â 1958.02), (b) death (aOR 28.06, 95% CI: 14.77-53.29), (c) pregnancy (aOR 16.90, 95% CI: 9.54-29.94), (d) illness onset in rainy season (aOR 0.33, 95% CI: 0.23-0.46). The implications for positive social change entail using present findings to guide clinical screening of HEV cases and to inform the effective deployment of the HEV intervention toolkit, including HEV vaccines that reduce the impact of HEV in displaced populations.