Fig. 5
Long-term projection of SARS-CoV-2 in the Republic of Korea by varying the maximum reproduction number of the Delta variant (Rmax). Projected waves of SARS-CoV-2 infection given the full lifting of interventions with three epidemiological outcomes: the newly reported cases, the prevalence of severe cases, and the cumulative number of deaths from 13 June 2021. In each projection, the reproduction number of the Delta variant was assumed to follow the logistic growth function with the 2 months of gradual increase and the varied maximum value: A–C Rmax =3.0, D–F Rmax =3.25, and G–I Rmax =3.5. In each figure, blue, red, and green lines and shaded areas indicate projected outcomes and their 95% confidence intervals given the reduction in transmissibility of SARS-CoV-2 variants by 30, 35, and 40%, respectively, due to the implementation of Level 4 social distancing. In addition, the pink shaded area shows the period in which Level 4 social distancing countermeasures were implemented, whereas the purple shaded area represents the period for gradual relaxation (fixed at 2 months)