Evaluation of Immunogenicity by Pseudovirus Neutralization Assays for SARS‐CoV‐2 Variants after Primary and Booster Immunization

•A large-scale long-term prospective cohort study on inactivated COVID-19 vaccine.•Two-dose inactivated vaccine induced the formation of neutralizing antibodies (NAbs).•Memory-associated immune responses of inactivated vaccines were documented.•High titers of NAbs against the variants obtained after booster immunization.