COVID-19 basic reproduction number and assessment of initial suppression policies in Costa Rica

¹ Vigilancia de la Salud, Ministerio de Salud, San José, San José, Costa Rica.
² Unidad de Análisis Epidemiolόgico y Bioestadística, Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panamá.
³ Universities Space Research Association, Columbia, MD 21046, USA.
⁴ Servicio de Infectología, Hospital Nacional de Niños, San José, Costa Rica.
⁵ Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, USA.

^* Corresponding author: lfchavs@gmail.com

Received: 7 April 2020
Accepted: 7 May 2020

Abstract

SARS-COV-2 is the most recent from a series of emerging pathogens stressing national health systems. Initially restricted to Hubei province in China, COVID-19, the disease caused by SARS-COV-2 has become pandemic, reaching almost every nation on our planet. Here, we present an estimate of the Basic Reproduction Number (R₀) for this disease based on confirmed cases recorded during the initial 30 days of transmission. Based on local transmission data for the six initial days of transmission, we estimated (mean ± SE) R₀ = 2.58 ± 2.43. R₀ was reduced by up to 56% to R₀ = 1.12 ± 0.02 following suppression measures in place by April 4th, 2020. Independent estimates for the time-varying reproduction number (R_t) based on the serial interval distribution estimated for China showed that after 30 days, R_t decreased reaching a value of 0.914 ± 0.104 on April 4th, 2020. In this study, we also describe the suppression strategies in place in Costa Rica and compare their impacts with those implemented in Panamá and Uruguay, provided these three middle-income countries have similar demographic and economic indicators. However, these three countries have structurally different health systems and have resorted to different suppression measures against COVID-19. We compare the early epidemic growth curves in the three countries using an exponential deceleration model. We found the lowest epidemic growth rate in Costa Rica, followed by Panamá and then Uruguay, while the highest deceleration was observed in Uruguay, followed by Costa Rica and Panamá. We discuss how the unified, universal healthcare system of Costa Rica has been vital to successfully manage the early stage of the COVID-19 epidemic and call for the developments of precision public health tools to further improve epidemic health surveillance in Costa Rica.