The hepatitis E vaccine provided sustained protection against the virus for up to 4.5 years, found a follow-up study to a 2007 randomized trial that evaluated the short-term efficacy of the vaccine Hecolin. The initial phase 3 clinical trial randomly assigned 112 604 healthy adults aged 16 to 65 years in a 1:1 ratio to receive 3 doses of either a hepatitis E vaccine or a hepatitis B vaccine (the control group). The follow-up study assessed efficacy, immunogenicity, and safety for 54 months (Zhang J et al. N Engl J Med. 2015;372:914-922).
Slomski A. Hepatitis E Vaccine Effective for 4.5 Years. JAMA. 2015;313(16):1609. doi:10.1001/jama.2015.3855