Reactogenicity and Immunogenicity of Third Dose Vaccine Booster Following Two Doses of Inactivated Vaccines

It is a prospective open-labeled study, We intended to recruit the participants who completed 2 doses of inactivated COVID-19 vaccine 4-8 months before, and volunteered to receive the third dose of vaccine (inactivated vaccine, recombinant subunit protein vaccine or mRNA vaccine) into the experimental group, and the participants who completed 2 doses of inactivated COVID-19 vaccine 4-8 months before without a third dose of vaccination plan into the control group. Participants in the experimental group received the third dose of SARS-CoV-2 vaccination at baseline, and participants in the control group received no intervention. Each subject will be followed up for one year after enrollment, and neutralizing antibodies and total antibodies will be tested at the specified time points, as well as the records of adverse events and adverse reactions.