The effect of early-stage public health policies in the transmission of COVID-19 for 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 ( R ₀ ) and time-varying ( R _t ) 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 R ₀ values during the first two weeks of the outbreak and R _t values 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. R ₀ ranged from 1.52 (95% confidence interval: 1.13-1.99) in Venezuela to 3.83 (3.04-4.75) in Chile, whereas R _t 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 R ₀ and R _t values may be related to the testing capacity of each country.
Conclusion: R ₀ 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 R _t over time in each country, albeit to different levels.