In October 2021, the Bill & Melinda Gates Foundation (BMGF) contracted the Strategic Analysis, Research, and Training Center (START) to characterize global HEV outbreaks and describe any data gaps to inform HEV vaccination strategies. The START Team performed a systematic review of peer-reviewed (PubMed, Embase) and gray literature (ProMed) to identify reports of outbreaks published between January 1, 2011, and November 15, 2021. The START Team screened 1,362 potentially relevant records after removing duplicates. Seventy-one reports were synthesized, which represented 41 outbreaks in 18 countries. Key outbreak epidemiological, response, and prevention characteristics were described, and major data gaps, publication bias, and missed opportunities were identified. Commonly missing data elements in the reports included specific case definitions used, testing strategy and methods, seroprevalence, and impacts of interventions.
HEV outbreaks represent a significant public health problem. However, the lack of data and standardized reporting mechanism significantly limits accurate estimation of disease burden, effective prevention, and response strategies. By identifying gaps around HEV outbreaks and response, the START Team hopes that future studies can address these action priorities. Deliverables include a Manuscript Draft with an Excel database of the HEV outbreaks, and a slide deck.