A Phase 1, Double-Blinded, Placebo-Controlled Clinical Trial to Evaluate the Safety and Immunogenicity of HEV-239 (Hecolin) Vaccine in Healthy US Adults

Background Establishing the safety and immunogenicity of a hepatitis E virus vaccine in multiple populations could facilitate broader access and prevent maternal and infant mortality.Methods We conducted a phase 1, randomized, double-blinded, placebo-controlled (4:1 vaccine to placebo) trial of 30 mu g HEV-239 (Hecolin, Xiamen Innovax Biotech Company Limited, China) administered intramuscularly in healthy US adults aged 18-45 years. Participants were vaccinated on days 1, 29, and 180. Participants reported solicited local and systemic reactions for 7 days following vaccination and were followed through 12 months after enrollment for safety and immunogenicity (IgG, IgM).Results Solicited local and systemic reactions between treatment and placebo group were similar and overall mild. No participants experienced serious adverse events related to HEV-239. All participants receiving HEV-239 seroconverted at 1 month following the first dose and remained seropositive throughout the study. HEV-239 elicited a robust hepatitis E IgG response that peaked 1 month following the second dose (geometric mean concentration [GMC], 6.16; 95% confidence interval [CI], 4.40-8.63), was boosted with the third dose (GMC, 11.50; 95% CI, 7.90-16.75) and persisted through 6 months.Conclusions HEV-239 is safe and elicits a durable immune response through at least 6 months after the third dose in healthy US adults.Clinical Trials Registration NCT03827395. In this phase 1, randomized, double-blinded, placebo-controlled trial, the recombinant hepatitis E virus vaccine (HEV-239) was found to be safe and immunogenic through at least 6 months in healthy US adults.