Figure 1

Vaccination timeline in South Korea; approval of four different types of vaccines; time-series of number of vaccinated people; and reported adverse events in the Gyeonggi province. A nationwide vaccination campaign for SARS-CoV-2 in South Korea was initiated on February 26th, 2021. Vaccines from four different manufacturers were approved: the viral vector-based ChAdOx1-S/nCoV-19 (Oxford-Astrazeneca) vaccine on February 10th, 2021; the BNT162b2 (Pfizer-BioNTech) vaccine on March 5th, 2021; the Ad26. COV2.S (Janssen) vaccine on April 7th, 2021; and the mRNA-1273 (Moderna) vaccine on May 21st, 2021. The initiation of each vaccine is represented by red and blue markers (red indicates mRNA-based and blue indicates viral vector-based). The slashed square area represents a temporary halt in the BNT162b2 vaccination in May 2021, owing to problems with vaccine supply. From the beginning of October, booster shots were given; most were mRNA vaccines (bold green line and arrow), and viral-vector vaccines (third dose of ChAdOx1-S/nCoV-19, an additional dose of Ad26.COV2.S) only represented a minority of vaccinated people (green dotted line and arrow). The gray bars in the background represent the total number of vaccinated people in the Gyeonggi province, South Korea, in the respective months.