Waning anti-SARS-CoV-2 receptor-binding domain total antibody in CoronaVac-vaccinated individuals in Indonesia.

: The decrease of immunity acquired from COVID-19 vaccines is a potential cause of breakthrough infection. Understanding the dynamics of immune responses of vaccine-induced antibodies post-vaccination is important. This study aimed to measure the level of anti-SARS-CoV-2 receptor-binding domain (RBD) total antibody in individuals at different time points upon the receipt of the second dose of CoronaVac vaccine, as well as evaluate the plausible associated factors.