The effect of early-stage public health policies on the transmission of COVID-19 in South American countries

Objectives: The analysis of transmission dynamics is crucial to determine whether mitigation or suppression measures reduce the spread of Coronavirus disease 2019 (COVID-19). This study sought to estimate the basic (R0) and time-varying (Rt) reproduction number of COVID-19 and contrast the public health measures for ten South American countries. Methods: Data was obtained from the European Centre for Disease Prevention and Control. Country-specific R0 estimates during the first two weeks of the outbreak and Rt estimates after 90 days were estimated. Results: Countries used a combination of isolation, physical distancing, quarantine, and community-wide containment measures to staunch the spread of COVID-19 at different points in time. R0 ranged from 1.52 (95% confidence interval: 1.13-1.99) in Venezuela to 3.83 (3.04-4.75) in Chile, whereas Rt after 90 days ranged from 0.71 (95% credible interval: 0.39-1.05) in Uruguay to 1.20 (1.19-1.20) in Brazil. Different R0 and Rt values may be related to the testing capacity of each country. Conclusion: R0 in the early phase of the outbreak varied across the South American countries. The public health measures adopted in the initial period of the pandemic appear to have reduced Rt over time in each country, albeit to different levels.