A vaccine licensed in China protected healthy adults against hepatitis E virus infection for up to 4.5 years, according to newly published data.
“Vaccine development has been facilitated by the observation that all major genotypes of HEV in humans belong to the same serotype,” the researchers wrote.
“Two recombinant hepatitis E vaccines developed from HEV genotype 1 by GlaxoSmithKline and Ziamen Innovax Biotech have had short-term efficacy in clinical trials. The latter vaccine, with the commercial name of Hecolin, has been in use in China since 2012. However, the long-term efficacy of this hepatitis E vaccine has not yet been determined.”
Researchers randomly assigned 56,302 healthy adults to the HEV vaccine group in which they received three doses of Hecolin (Xiamen Innovax Biotech) at baseline, 1 month and 6 months. An additional 56,302 healthy adults were assigned to a control group in which they received a hepatitis B vaccine in three doses at the same time as the vaccine group. The patients were followed for 19 months and in an extended follow-up study, follow-up continued for up to 4.5 years.
After 19 months of the study, data analyses completed by researchers led to the licensure of Hecolin in China for protection against HEV, according to the research.
During the 4.5-year extended follow-up study period, 60 cases of HEV developed among the cohorts, including 23 from the initial study and 37 in the extended study. Seven cases developed in the HEV vaccine group, whereas 53 developed in the control group. The cumulative incidence rate of HEV was lower in the vaccine group compared with the control group (P < .001). In the seven patients who received the vaccine and still developed HEV, three had received all three doses, one patient received two doses and three had received only one, according to the research.
HEV vaccine efficacy was 86.8% according to the modified intention-to-treat analysis, 85.1% in the intention-to-treat analysis and 93.3% in the per-protocol analysis.
In the vaccine group, 5,567 patients were tested for immunogenicity and 52% were seronegative at baseline. Of these patients, 99.9% underwent seroconversion after vaccination and 87% of these were seronegative at baseline and received all three doses of the HEV vaccine. These patients maintained seropositive through 4.5 years of follow-up.
Vaccine efficacy did not appear to wane over time and no concerns about the safety of the vaccine were observed or reported.
“Immunization with the hepatitis vaccine we tested induced a sustained level of antibodies and protection against hepatitis E for up to 4.5 years,” the researchers concluded.
Disclosure: The study was funded through grants from the Chinese Ministry of Science and Technology National Major Scientific and Technological Special Project, National Natural Science Foundation of China, National High-tech Research and Development Program and Jiangsu Science and Technology Support Program.