Introduction
HEV infection, viral hepatitis, Hepatitis E, infection, HEV infections, deaths
HEPATITIS E, VIRUS, VIRAL HEPATITIS, HEPATITIS E, INFECTION
Hepatitis E (HE) is a common viral hepatitis caused by the hepatitis E virus (HEV) infection. There are an estimated 20 million HEV infections worldwide every year, leading to approximately 3.3 million symptomatic cases and 44,000 deaths [A recombinant HE vaccine (Hecolin; Xiamen Innovax, Xiamen, China), which has been licensed in 2011 and 2020 in China and Pakistan, separately, is the world’s first and only vaccine to prevent HEV infection. It has been demonstrated with good safety and an efficacy of 100% within 12 months after the third dose in a large-scale, randomized, double-blind, placebo-controlled, phase 3 trial [Therefore, with a view to further investigation of the potential risk posed by HE vaccination during or shortly before pregnancy, we conducted a post-hoc analysis of pregnancy outcomes based on a large-scale phase 3 clinical trial of an 