Predictions, role of interventions and effects of a historic national lockdown in India's response to the COVID-19 pandemic: data science call to arms

Debashree Ray; Maxwell Salvatore; Rupam Bhattacharyya; Lili Wang; Shariq Mohammed; Soumik Purkayastha; Aritra Halder; Alexander Rix; Daniel Barker; Michael Kleinsasser; Yiwang Zhou; Peter Song; Debraj Bose; Mousumi Banerjee; Veerabhadran Baladandayuthapani; Parikshit Ghosh; Bhramar Mukherjee

Under national lockdown (March 25 -April 14), our predicted cumulative number of COVID-19 cases in India on April 30 are 9,181 and 11,626 (upper 95% CI of 72,245 and 84,245) assuming a 1-or 2-week delay (i.e., either a quick or a slow adherence), respectively, in people's adherence to lockdown restrictions and a gradual, moderate resumption of daily activities post-lockdown (Figure 4, Supplementary Figure 1 ). In comparison, the predicted cumulative number of cases under "no intervention" and the "intervention involving social distancing and travel bans without lockdown" are 358 thousand and 46 thousand (upper 95% CI of nearly 2.3 million and 0.3 million) respectively. We are reporting only the upper credible limit here and elsewhere since the lower credible limits are very close to 0 due to the large uncertainty in our predictions arising from many unknowns. We also believe that our point estimates are at best underestimates due to potential under-reporting of case-counts and our model not taking into account the population density, agesex and contact network structure of the whole nation. Increase in testing and community transmission may lead to a spike in a single day and that may shift the projection curve significantly upward. Regardless of the exact numbers it is clear that, the 21-day lockdown will likely have a strong effect on reducing the predicted number of cases in the short term.