The 2019 Coronavirus disease outbreak (COVID-19) was first reported at the end of 2019 in Wuhan China as a severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection. In less than a year, SARS-CoV-2 infection has become a pandemic and spread to almost all countries in the world, including Indonesia. World Health Organization data states that there are 4,240,479 confirmed cases of SARS-CoV-2 in Indonesia until 25 October 2021 with a death rate of 143,235 (WHO, 2021a).
The Indonesian National Agency of Drug and Food Control (NA-DFC) has issued an Emergency Use Authorization for several SARS-COV-2 Vaccines, including the SARS-CoV-2 vaccine (Vero cell) inactivated produced by Sinopharm (BPOM, 2021). Clinical data that the actual immune responses decrease after several months are continuously being reported (Marmot et al., 2021), and the decrease of vaccine efficacy due to the appearance of variants is also known (Abu-Raddad et al., 2021; Lopez Bernal et al., 2021). These potential risks suggest the need for a booster dose or periodic booster doses of the SARS-COV-2 Vaccine. In fact, there is a study result given several months after vaccination, which leads to the generation of a higher immune responses (Pan H et al., 2021). Booster dose of SARS-COV-2 Vaccine will either induce a high level of antibody responses against original strain, or enhance the broadly formed T cell immunity regardless of mutant strain to improve individual protection.