Antibody response to the inactivated SARS-CoV-2 vaccine among healthcare workers, Indonesia

Cucunawangsih, Cucunawangsih; Wijaya, Ratna Sari; Lugito, Nata Pratama Hardjo; Suriapranata, Ivet

Background As healthcare workers (HCWs) are at high risk for SARS-CoV-2 infection, they have prioritized the COVID-19 vaccine. Inactivated SARS-CoV-2 vaccine has been mainly used in Indonesia to induce HCWs antibody response against SARS-CoV-2 infection. However, information regarding the kinetics of antibody-induced by this vaccine remains scarce. Objective To investigate the magnitude and durability of antibodies against spike (S) protein (anti-S) after complete dose of vaccination among HCWs by using the electrochemiluminescence immunoassay. Results Seroconversion of anti-S antibodies was observed among 159 (99.4%) of 160 HCWs after 14 days of full-dose vaccination. The levels of anti-S antibodies significantly decreased after day 42 compared to day 14 post-vaccination, but it persisted up to 98 days following vaccination. In contrast, the vaccinated HCWs with prior SARS-CoV-2 infection had significantly higher and stably elevated anti-S antibodies concentrations than vaccinated HCWs without SARS-CoV-2 infection history. Conclusion The remarkable decline and lower anti-S antibodies concentration among infection-naïve HCWs potentially indicate the additional booster dose of SARS-CoV-2 vaccination may be required to ascertain COVID-19 protection among HCWs by this vaccine. This early study of antibody response induced by inactivated SARS-CoV-2 vaccine among HCWs potentially contributes to the future policy decision regarding vaccination.