Immunogenicity and Safety of Hepatitis A Among People Aged 18-50 Years Old

The Immunogenicity and Safety of Different Vaccination Interval of Inactivated Hepatitis A Vaccine in People Aged 18-50 Years, a Phase IV Clinical Trial

This study is conducted among people aged 18-50 in Dandong City, an area with a high incidence of hepatitis A in recent years. 1000 qualified pariticipants with signed informed consent will be screened for anti-HAV antibodies by collecting blood sample of 3ml. One dose of hepatitis A vaccine will be administrated to all the pariticipants. Negative anti-HAV antibodies-negative subjects will recieve the second dose of hepatitis A vaccination, and 400 of them will be randomly selected and assigned to 4 groups with different interval of vaccination(6 month, 18 months, 36 months and 60 months). Blood samples will be collected before vaccination of each dose and on 28 days after each dose of vaccination to anti-HAV antibody test. Safety data will be collected within 28 days after each vaccination with a smartphone mini-program.

Inclusion Criteria:

• Adults aged 18-50;
• Adults can understand and sign the informed consent form voluntarily;
• Adults can provide valid and legal identity certificate.

Exclusion Criteria:

• A history of hepatitis A infection;
• Previously vaccinated with inactivated hepatitis A vaccine, live attenuated hepatitis A vaccine, or hepatitis A and B combined vaccine;
• Allergic constitution or have severe allergic reaction to vaccines in the past (such as acute allergic reaction, angioedema, dyspnea, etc.);
• Pregnant women and lactating women;
• People suffering from uncontrolled epilepsy and other serious neurological diseases (such as transverse myelitis, Guillain-Barré syndrome, demyelinating diseases, etc.);
• Patients with fever during vaccination, or acute exacerbation of chronic diseases, or patients with uncontrolled severe chronic diseases, or suffering from acute diseases;
• Received other research drugs within 30 days before vaccination with the experimental vaccine;
• Have received a live attenuated vaccine within 14 days before vaccination with the experimental vaccine;
• Have received subunit or inactivated vaccine within 7 days before vaccination with experimental vaccine;
• Other conditions that are not suitable for vaccination judged by the researcher.