Antibody Response to CoronaVac Vaccine in Indonesian COVID-19 Survivor

Several studies have shown that individuals with previous history of SARS-CoV-2 infection had boosted antibody response after single dose of mRNA or adenovirus-vectored vaccines. We wondered whether single dose CoronaVac, a whole-inactivated vaccine, could be considered for COVID-19 survivors in Indonesia. We measured IgG anti-RBD titre among 18 survivors and 37 non-survivors. Among survivors, there were 9 survivors with positive antibody titre (seropositive) before vaccination and 9 seronegative survivors. All respondents received two doses of CoronaVac vaccine at 14-days interval. We found no significant antibody titre difference between non-survivor at 14 or 28 days after second dose as well as seronegative survivor at at 14 days after second dose. Seropositive survivors were rapidly boosted after first dose with higher antibody titer than non-survivors and seronegative survivors after second dose. However, antibody titer did not differ between first and second dose among seropositive survivors. Seropositive COVID-19 survivors could receive single dose of CoronaVac vaccine which could potentially ease the vaccine supply constrain. A long-term follow-up must be conducted to observe difference in antibody response and persistence. Article Summary LineSeropositive COVID-19 survivors had significantly higher antibody response after first dose of CoronaVac vaccine compared to non-survivors and seronegative survivors after second dose of vaccine.