Seroconversion of the CoronaVac? Vaccine from One Dose in an Outbreak of COVID-19 Infection at a Long-term Care Institution

The purpose of this study is to assess the vaccine response to the COVID-19 outbreak installed at the institution. To conduct this case report, 36 individuals were evaluated, among residents and employees of this institution. Blood samples were collected by venipuncture and the presence of antibodies to SARS-CoV-2 (total antibodies, IgG and IgM) were analysed in these samples; 25% of patients/staff (n = 9) seroconverted with only the first dose of CoronaVac (R) in just 14 days after the first dose of the vaccine. These individuals did not developed symptoms of COVID-19 during the outbreak that occurred at the institution. Vaccine response to CoronaVac (R), after an outbreak of COVID-19 at the studied institution, was higher than the response postulated in other previously published studies with detection of SARS-CoV-2 antibodies before the second dose of the vaccine.