Doubling Time and Its Interpretation for COVID-19 Cases: A Comparative Study in Pimpri Chinchwad Municipal Corporation, Pune, Maharashtra, India

Background: COVID-19, also known as Novel Corona Virus, causes respiratory disorder in humans and has been declared as a global pandemic in the first quarter of the year 2020 by the World Health Organization. As this pandemic persists the second, third and fourth quarters had shown variation in COVID-19 cases. In the first quarter of the year 2021 again there seems to be a rise in cases of COVID-19. So, a comparative analysis from March 2020 – April 2021 of COVID-19 cases has been studied.

Methodology: An exponential statistical model was used to calculate the predicted value of COVID-19 using doubling time for a short duration. The cases of COVID-19 were predicted from 10th April 2021 to 10th June 2021 using doubling time and exponential regression method.

Results: The distribution of cases showed a curve-linear trend over the last one year. We explored various models like exponential, logarithmic (lo-linear), linear, quadratic, and generalized linear model (GLM) to fit into the observed distribution of cases. Since the distribution of cases was perfectly following a linear trend in each of the four segments, we applied a linear regression model to observed distribution and then predicted the anticipated no. of cases by extending this linear trend to a future period (120 day). With the help of the exponential statistical model, doubling time/rate based on prior 9 days, the predictions of up to 2.61 lakhs cases have been done by the end of June 2021.

Conclusion: This study will be useful for the Government of India and Maharashtra state-specific to Pimpri- Chinchwad Municipal Corporation (PCMC), Administrative Units, Frontline health workforce, researchers, and scientists. From this study it has been evident that during the pre-lockdown period, in the initial stages there seems to be rise in cases. While, during lockdown period it was observed that there was relatively decrease in the number of cases. After the government authorities imposed the unlock strategies the cases began to rise as compared to the lockdown period. Thus, it appears that only essential services should be open for the citizens of India and the state lockdown should be carried on for the next 3 months (April 2021 - June 2021).