Hybrid Immunity Results in Enhanced and More Sustained Antibody Responses after the Second Sinovac-CoronaVac Dose in a Brazilian Cohort: DETECTCoV-19 Cohort

We measured anti-SARS-CoV-2 antibody responses before and after CoronaVac (inactivated) vaccination in a case–control study performed CoronaVac-immunized individuals participating longitudinal prospective of adults Manaus (DETECTCoV-19). Antibody were by standard serological immunoassays. Peak anti-S-RBD neutralizing RBD-ACE2 blocking two doses vaccine similar breakthrough cases (n = 9) matched controls 45). Individuals with hybrid immunity resulting from prior SARS-CoV-2 infection followed 22) had elevated levels anti-N, antibodies the second dose compared to infection-naïve 48). Post-vaccination SARS-CoV-2-specific rapidly waned individuals. wane vaccination, making susceptible variants. These findings support need for booster primary vaccination. Population serosurveys provide critical information toward implementing optimal timing doses.