1. Overall vaccine efficacy ranged from 83.1% to 86.6% during the 10-year period.

2. Detectable concentrations of antibodies persisted at the 8.5-year mark in Qindong.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis worldwide. Currently, two recombinant HEV vaccines exist; however, little is known about their long-term safety and efficacy. This randomized controlled trial aimed to assess the durability of hepatitis E vaccine efficacy over 10 years in a Chinese population. The primary outcome of this study was the per-protocol efficacy of the vaccine in preventing confirmed hepatitis E, while a key secondary outcome was the persistence of vaccine-induced antibodies. According to study results, the hepatitis E vaccine provided durable protection for up to 10 years, with vaccine-induced antibodies persisting for up to eight and a half years in a majority of participants. Although this study was well done, it was limited by the geographical scope of the study population.

Click to read the study in The Lancet

Relevant Reading: Safety and Efficacy of a Recombinant Hepatitis E Vaccine

In-depth [randomized-controlled trial]: Between Aug 22, 2007, and Oct 31, 2017, 112 604 patients were assessed for eligibility across 11 townships in Dongtai County, China. Included were patients from Dongtai County, Jiangsu, China, aged 16–65 years, with no contraindication to the hepatitis E vaccine. Altogether,
112 604 patients were included in the final analysis. After the 10-year follow-up period, 90 patients were diagnosed with hepatitis E with 13 in the vaccine group and 77 in the placebo group. The primary outcome of per-protocol vaccine efficacy was 83.1% (95% confidence interval [CI] 69.4-91.4) in the modified intention-to-treat analysis and 86.6% (95% CI 73.0-94.1) in the per-protocol analysis. Moreover, the secondary outcome revealed that 87.3% (254 of 291) of vaccinees in Qindong maintained detectable concentrations of antibodies for up to 8.5 years. Findings from this study suggest that the hepatitis E vaccine provides durable protection against HEV for up to 10 years, with sustained antibody levels.

Image: PD

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