Dynamics of SARS-COVID-19 pandemic in the province of Buenos Aires based on the effective reproductive number (Rt)

Abstract

INTRODUCTION: From the beginning of the COVID-19 pandemic until March 31, 2022, a total of 3542289 cases were reached in the province of Buenos Aires, and 59746 died. One of the measurements included in the surveillance was the estimation of the effective reproductive number (Rt), which provides information about the speed with which a disease can spread. The objective of this study was to estimate the variation of Rt, doubling time and contagion rate as an expression of the dynamics of the COVID-19 pandemic from March 2020 to March 2022 in the province of Buenos Aires. METHODS: The Rt was estimated over sliding weekly windows, with a parametric serial interval mean of 4.8 days and a standard deviation of 2.3. The doubling time applied the logarithm function (ln) because it was assumed that the increase of the number of cases followed an exponential distribution. The contagion rate was calculated from a linear regression of the ln of the cases accumulated in periods of 7 days. RESULTS: A total of 3495338 confirmed cases were studied. There were three moments where Rt>1. DISCUSSION: As the pandemic progressed, Rt could be estimated in real time and showed how it evolved over the two years of the pandemic according to the waves, that occurred three times during the historical window analyzed.