Setting a Course for Preventing Hepatitis E in Low and Lower-Middle-Income Countries: A Systematic Review of Burden and Risk Factors

Abstract

Background Hepatitis E virus is responsible for outbreaks of acute jaundice in Africa and Asia, many of which occur among displaced people or in crisis settings. While an efficacious vaccine for HEV has been developed, we lack key epidemiologic data needed to understand how best to use the vaccine for hepatitis E control in endemic countries. Methods We conducted a systematic review of articles published on hepatitis E in low and lower-middle-income countries (LMIC) in Africa and Asia. We searched PubMed, Scopus, and Embase databases to identify articles with data on anti-HEV IgG seroprevalence, outbreaks of HEV, or risk factors for HEV infection, disease, or death, and all relevant data were extracted. Using these data we describe the evidence around temporal and geographical distribution of HEV transmission and burden. We estimated pooled age-specific seroprevalence and assessed the consistency in risk factor estimates. Results We extracted data from 148 studies. Studies assessing anti-HEV IgG antibodies used 18 different commercial assays. Most cases of hepatitis E during outbreaks were not confirmed. Risk factor data suggested an increased likelihood of current or recent HEV infection and disease associated with fecal-oral transmission of HEV, as well as exposures to blood and animals. Conclusion Heterogeneity in diagnostic assays used and exposure and outcome assessment methods hinder public health efforts to quantify burden of disease and evaluate interventions over time and space. Prevention tools such as vaccines are available, but require a unified global strategy for hepatitis E control to justify widespread use.

Hepatitis E in Bangladesh: Insights From a National Serosurvey

“…If this hypothesis is correct, household-level water and sanitation interventions alone may not be sufficient to interrupt HEV transmission. Water and sanitation interventions may also have limited utility in preventing sporadic acute hepatitis cases associated with exposure to blood and animals, which are hypothesized to contribute to the burden of hepatitis E in Bangladesh [ 32 ] and other LMICs [ 33 ].…”

“…We assumed that these serologic assays had perfect sensitivity and specificity for detecting historical HEV infections. Previous studies have estimated sensitivity and specificity of these assays to be high [ 33 , 34 ]; however, without a gold standard assay to compare against these estimates are unlikely to be perfect nor generalizable to all settings. Furthermore, seropositivity has been shown to decay over time so those infected many years before the serosurvey may be differentially misclassified as seronegative [ 35 , 36 ].…”

Hepatitis E in immunocompromised individuals

“…Treatment of acute HEV at times can be imperative, especially in immunocompromised patients, as it can decrease the risk of chronic hepatitis, cirrhosis, and subsequently death[ 5 ]. A potentially effective vaccination strategy has been developed for HEV prevention, altering the incidence in Asian countries[ 6 ]. The World Health Organization (WHO) recommends consideration of vaccination for high-risk patients such as pregnant women[ 7 ].…”

Annual risk of hepatitis E virus infection and seroreversion: Insights from a serological cohort in Sitakunda, Bangladesh

“…Hepatitis E virus (HEV) is an important cause of acute jaundice in populations with limited access to safe drinking water across South Asia and Africa [1][2][3][4][5]. Transmitted from person-toperson via faecal-contaminated water, HEV genotypes 1 and 2 (HEV-1 and 2) carry a high risk of death if contracted during pregnancy [6] and regularly cause outbreaks, with particularly longlasting transmission documented in displaced persons camps [7]. In Bangladesh, HEV is the leading cause of hospital-attended acute jaundice [3].…”