Hepatitis E vaccine offers durable protection

Vaccination against hepatitis E appears to provide up to 10 years of protection, with vaccine-induced antibodies persisting for at least 8.5 years, as shown in a study from China.

The study was an extension to a randomized, double-blind, placebo-controlled, phase III clinical trial involving 112,604 healthy adults between 16 and 65 years of age enrolled across multiple centres in China. These participants were randomly assigned to receive three doses of hepatitis E vaccine or placebo. Treatment was administered intramuscularly at baseline, month 1, and month 6. All participants were followed up for 10 years.

The primary outcome was the per-protocol efficacy of hepatitis E virus vaccine to prevent the incidence of hepatitis E infection at least 30 days after administration of the third dose.

Over 10 years of follow-up, 90 participants contracted hepatitis E infection, including 13 in the vaccine group and 77 in the placebo group, with incidence rates of 0.2 and 1.4 per 10,000 person-years, respectively.

The vaccine efficacy was 83.1 percent (95 percent confidence interval [CI], 69.4–91.4) in the modified intention-to-treat population and 86.6 percent (95 percent CI, 73.0–94.1) in the per-protocol population.

Among the participants who were seronegative at baseline and received three doses of hepatitis E vaccine, 87.3 percent of those in the Qindong area and 73.0 percent of those in the Anfeng area maintained detectable concentrations of antibodies at the 8.5- and 7.5-year mark, respectively.