Protection against hepatitis E virus infection by naturally acquired and vaccine-induced immunity
J Zhang, X-F Zhang, C Zhou, Z-Z Wang, S-J Huang, X Yao, Z-L Liang, T Wu, J-X Li, Q Yan, C-L Yang, H-M Jiang, H-J Huang, Y-L Xian, J W-K Shih, M-H Ng, Y-M Li, J-Z Wang, F-C Zhu, N-S Xia, J Zhang, X-F Zhang, C Zhou, Z-Z Wang, S-J Huang, X Yao, Z-L Liang, T Wu, J-X Li, Q Yan, C-L Yang, H-M Jiang, H-J Huang, Y-L Xian, J W-K Shih, M-H Ng, Y-M Li, J-Z Wang, F-C Zhu, N-S Xia
Abstract
Immunity acquired from infection or vaccination protects humans from symptomatic hepatitis E. However, whether the risk of hepatitis E virus (HEV) infection is reduced by the immunity remains unknown. To understand this issue, a cohort with 12 409 participants randomized to receive the hepatitis E vaccine Hecolin(®) or placebo were serologically followed up for 2 years after vaccination. About half (47%) of participants were initially seropositive. A total of 139 infection episodes, evidenced by four-fold or greater rise of anti-HEV level or positive seroconversion, occurred in participants who received three doses of treatment. Risk of infection was highest among the baseline seronegative placebo group participants (2.04%). Pre-existing immunity and vaccine-induced immunity lower the risk significantly, to 0.52% and 0.30%, respectively. In conclusion, both vaccine-induced and naturally acquired immunity can effectively protect against HEV infection.
Keywords: Antibody level; hepatitis E virus; immunity; infection; vaccine.
© 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.
Source: PubMed