A Comprehensive Public Health Evaluation of Lockdown as a Non-pharmaceutical Intervention on COVID-19 Spread in India: National Trends Masking State Level Variations

Abstract

Introduction: India has been under four phases of a national lockdown from March 25 to May 31 in response to the COVID-19 pandemic. Unmasking the state-wise variation in the effect of the nationwide lockdown on the progression of the pandemic could inform dynamic policy interventions towards containment and mitigation.

Methods: Using data on confirmed COVID-19 cases across 20 states that accounted for more than 99% of the cumulative case counts in India till May 31, 2020, we illustrate the masking of state-level trends and highlight the variations across states by presenting evaluative evidence on some aspects of the COVID-19 outbreak: case-fatality rates, doubling times of cases, effective reproduction numbers, and the scale of testing.

Results: The estimated effective reproduction number R for India was 3.36 (95% confidence interval (CI): [3.03, 3.71]) on March 24, whereas the average of estimates from May 25 - May 31 stands at 1.27 (95% CI: [1.26, 1.28]). Similarly, the estimated doubling time across India was at 3.56 days on March 24, and the past 7-day average for the same on May 31 is 14.37 days. The average daily number of tests have increased from 1,717 (March 19-25) to 131,772 (May 25-31) with an estimated testing shortfall of 4.58 million tests nationally by May 31. However, various states exhibit substantial departures from these national patterns.

Conclusions: Patterns of change over lockdown periods indicate the lockdown has been effective in slowing the spread of the virus nationally. The COVID-19 outbreak in India displays large state-level variations and identifying these variations can help in both understanding the dynamics of the pandemic and formulating effective public health interventions. Our framework offers a holistic assessment of the pandemic across Indian states and union territories along with a set of interactive visualization tools that are daily updated at covind19.org.

Figure 1.. Daily number of reported cases, fatalities, and recovered cases in India over the period between March 15 and May 31 with four states showing the variation.

Punjab is an example state of “doing well” whereas case-counts in Delhi and Maharashtra are still increasing. Kerala was doing well initially but has seen a recent surge of cases.

Figure 2.. National estimates of doubling times and time-varying R.

Panel a. Estimated doubling times of total number COVID-19 cases in India, with averages for the pre and post-lockdown periods and past 7-day average as of May 31. Panel b. Estimated time-varying R (effective basic reproduction number) for COVID-19 in India with averages for the pre- and post-lockdown periods and past 7-day average as of May 31, along with 95% confidence intervals.

Figure 3.. State-wise estimates of doubling times and time-varying R.

Panel a. Estimated doubling times of total number COVID-19 cases in 20 Indian states and union territories. Panel b. Estimated time-varying R (effective basic reproduction number) for COVID-19 in 20 Indian states and union territories along with 95% confidence intervals.

Figure 4.. Testing summaries.

Panel a. Time series plot of test positive rates for India over the period between April 1 and May 31. Panel b. Shortfall of number of tests across 20 Indian states and union territories, relative to a benchmark test positive rate of 2%, along with a national estimate. Based on testing data up to May 31.

Figure 5.. Forest plot dashboard.

Panel a. Forest plot of estimated case-fatality rates (CFR1) based on all confirmed cases as of May 31, along with 95% confidence intervals, for 20 states and union territories of India, and a national summary. Panel b. Forest plot of estimated doubling times (in days) based on data from a 7-day past window from May 31, along with 95% confidence intervals, for 20 states and union territories of India, and a national summary. Panel c. Forest plot of estimated time-varying R (effective basic reproduction number) based on data from a 7-day past window from May 31, along with 95% confidence intervals, for 20 states and union territories of India, and a national summary. Panel d. Forest plot of test positive rates (proportion scale) based on data as of May 31, for 20 states and union territories of India, along with a national summary.