Fig. 1

Course of the COVID-19 pandemic in Chile and details of the participants of this study. A Chile had three waves of COVID-19. The black curve depicts the daily cases of COVID-19, while the red curve represents deceased people due to COVID-19 during the period. B Characteristics of the volunteers participating in different stages of this study. Group 1 was composed of health care personal from HLF and was designed to test pre-immunization with CoronaVac, 1 month after the first and 1 month after the second dose. Group 2 contains samples from healthy donors recruited to compare the antibody response to CoronaVac and BNT162b2 1 month after the second dose. In group 3, the effect of homologous or heterologous booster schemes in the antibody response of individuals vaccinated 6 months before with two doses of CoronaVac was determined. Samples were collected 20 days after the booster. In group 4, the antibody response was determined 100 days after the booster date in individuals who received two-doses of the CoronaVac vaccine originally. Arrows indicate times of sample collection. Details of the volunteers participating in the study is indicated in the table