Long-term efficacy of a hepatitis E vaccine
Jun Zhang, Xue-Feng Zhang, Shou-Jie Huang, Ting Wu, Yue-Mei Hu, Zhong-Ze Wang, Hua Wang, Han-Min Jiang, Yi-Jun Wang, Qiang Yan, Meng Guo, Xiao-Hui Liu, Jing-Xin Li, Chang-Lin Yang, Quan Tang, Ren-Jie Jiang, Hui-Rong Pan, Yi-Min Li, J Wai-Kuo Shih, Mun-Hon Ng, Feng-Cai Zhu, Ning-Shao Xia, Jun Zhang, Xue-Feng Zhang, Shou-Jie Huang, Ting Wu, Yue-Mei Hu, Zhong-Ze Wang, Hua Wang, Han-Min Jiang, Yi-Jun Wang, Qiang Yan, Meng Guo, Xiao-Hui Liu, Jing-Xin Li, Chang-Lin Yang, Quan Tang, Ren-Jie Jiang, Hui-Rong Pan, Yi-Min Li, J Wai-Kuo Shih, Mun-Hon Ng, Feng-Cai Zhu, Ning-Shao Xia
Abstract
Background: Hepatitis E virus (HEV) is a leading cause of acute hepatitis. The long-term efficacy of a hepatitis E vaccine needs to be determined.
Methods: In an initial efficacy study, we randomly assigned healthy adults 16 to 65 years of age to receive three doses of either a hepatitis E vaccine (vaccine group; 56,302 participants) or a hepatitis B vaccine (control group; 56,302 participants). The vaccines were administered at 0, 1, and 6 months, and the participants were followed for 19 months. In this extended follow-up study, the treatment assignments of all participants remained double-blinded, and follow-up assessments of efficacy, immunogenicity, and safety were continued for up to 4.5 years.
Results: During the 4.5-year study period, 60 cases of hepatitis E were identified; 7 cases were confirmed in the vaccine group (0.3 cases per 10,000 person-years), and 53 cases in the control group (2.1 cases per 10,000 person-years), representing a vaccine efficacy of 86.8% (95% confidence interval, 71 to 94) in the modified intention-to-treat analysis, rather than (95% confidence interval, 71 to 84) [corrected]. Of the participants who were assessed for immunogenicity and were seronegative at baseline, 87% of those who received three doses of the hepatitis E vaccine maintained antibodies against HEV for at least 4.5 years; HEV antibody titers developed in 9% in the control group. The rate of adverse events was similar in the two groups.
Conclusions: Immunization with this hepatitis E vaccine induced antibodies against HEV and provided protection against hepatitis E for up to 4.5 years. (Funded by the Chinese Ministry of Science and Technology and others; ClinicalTrials.gov number, NCT01014845.).
Source: PubMed