Fig. 3

Reconstructed epidemic curve and ascertainment ratio in India, 2021. A Estimated daily incidence of infection overlaid with officially reported number of documented cases by the government of India over the period from February 28 to July 3, 2021. Two vertical axes are calculated with the unit of 100,000 persons for the entire country of India. The green line with sticks represents estimated infections using dataset 1 of Kucirka et al. [29]. The dotted lines show the 95% confidence intervals (CI); however, this is mostly overlapped with estimates using dataset 3. The purple with diamond markers represents estimated infections using dataset 2 of Hellewell et al. [30] accompanied by 95% CI represented by dashed lines. Estimated infections using dataset 3 are derived using data of unvaccinated prisoners during an epidemic wave caused by the Delta variant in the United States, represented by the orange line with solid lines for the 95% CI [31]. Estimation 1 and estimation 3 were right-overlapped with each other. B Ascertainment ratio over time, calculated as the biweekly number of estimated infections over the biweekly reported number of documented cases; each observation period has three different estimates using three different datasets. The left-hand vertical axis represents the ascertainment ratio, and the right-hand vertical axis represents the number of documented cases. Ascertainment ratios 1, 2, and 3 correspond to estimates using datasets 1, 2, and 3, respectively