Persistence of antibodies acquired by natural hepatitis E virus infection and effects of vaccination.
OBJECTIVE
Naturally acquired anti-hepatitis E virus (HEV) immunity can protect against new HEV infections. The aim of this study was to analyse the persistence of naturally acquired anti-HEV immunoglobulin (Ig) G and anti-HEV IgG concentrations after vaccination.


METHODS
We examined the seropositivity rates of participants included in a phase 3 clinical efficacy trial (67 months' follow-up) for a HEV vaccine (Hecolin; Xiamen Innovax Biotech, China) and predicted long-term persistence using mixed-effect models.


RESULTS
The analysis focused on 2242 baseline seropositive participants in a control group (placebo recipients) and 2031 baseline seropositive participants in an vaccine group (vaccine recipients) who received 1 to 3 doses of Hecolin. Naturally acquired anti-HEV IgG levels decreased steadily independent of the initial antibody level; 50% of the placebo recipients were expected to have undetectable antibody concentrations after 14.5 years. After immunization with Hecolin, the power-law model and the modified power-law model predicted that 82.1 and 99.4% of the participants, respectively, would remain seropositive for anti-HEV IgG for 30 years after vaccination.


CONCLUSIONS
Whereas naturally acquired anti-HEV IgG levels decrease steadily, HEV vaccination induces long-lasting, high-level anti-HEV IgG concentrations.
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
Y-Y
YY
Su
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
S-J
SJ
Huang
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
M
M
Guo
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
J
J
Zhao
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
H
H
Yu
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
W-G
WG
He
Dongtai Centre for Disease Control and Prevention, Dongtai, China.
H-M
HM
Jiang
Dongtai Centre for Disease Control and Prevention, Dongtai, China.
Y-J
YJ
Wang
Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China.
X-F
XF
Zhang
Dongtai Centre for Disease Control and Prevention, Dongtai, China.
J-P
JP
Cai
Dongtai Centre for Disease Control and Prevention, Dongtai, China.
C-L
CL
Yang
Dongtai Centre for Disease Control and Prevention, Dongtai, China.
Z-Z
ZZ
Wang
Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China.
F-C
FC
Zhu
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China. Electronic address: wuting@xmu.edu.cn.
T
T
Wu
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China. Electronic address: zhangj@xmu.edu.cn.
J
J
Zhang
State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen, China.
N-S
NS
Xia
D016022:Case-Control Studies; D004306:Dose-Response Relationship, Immunologic; D005500:Follow-Up Studies; D006508:Hepatitis Antibodies / Q000097:blood*; D016751:Hepatitis E / Q000276:immunology*; D016752:Hepatitis E virus; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000627:therapeutic use*; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage / Q000627:therapeutic use*
D006508:Hepatitis Antibodies; D007074:Immunoglobulin G; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines; C577000:hecolin
Antibody level; Hepatitis E virus; Mathematical model; Persistence; Vaccine