The basic reproduction number (R0) is the number of cases directly caused by an infected individual throughout his infectious period. R0 is used to determine the ability of a disease to spread within a given population. The reproduction number (R) represents the transmissibility of a disease. We aimed to calculate the R0 of Coronavirus disease-2019 (COVID-19) in Sri Lanka and to describe the variation of R, with its implications to the prevention and control of the disease. Data was obtained from daily situation reports of the Epidemiology Unit, Sri Lanka and a compartmental model was used to calculate the R0 using estimated model parameters. This value was corroborated by using two more methods, the exponential growth rate method and maximum likelihood method to obtain a better estimate for R0. The variation of R was illustrated using a Bayesian statistical inference-based method. The R0 calculated by the first model was 1.02 [confidence interval (CI) of 0.75–1.29] with a root mean squared error of 7.72. The exponential growth rate method and the maximum likelihood estimation method yielded an R0 of 0.93 (CI of 0.77–1.10) and a R0 of 1.23 (CI of 0.94–1.57) respectively. The variation of R ranged from 0.69 to 2.20. The estimated R0 for COVID-19 in Sri Lanka, calculated by three different methods, falls between 0.93 and 1.23, and the transmissibility R has reduced, indicating that measures implemented have achieved a good control of disease.

中文翻译：

---

斯里兰卡新型冠状病毒病的基本繁殖数（R0）估算

基本繁殖数（R0）是感染个体在整个感染期间直接引起的病例数。R0用于确定疾病在给定人群中传播的能力。繁殖数（R）代表疾病的传播性。我们的目的是计算斯里兰卡的冠状病毒病-2019（COVID-19）的R0并描述R的变异，及其对疾病预防和控制的意义。数据来自斯里兰卡流行病学部门的每日情况报告，并使用隔室模型使用估计的模型参数来计算R0。通过使用两种其他方法（指数增长率方法和最大似然方法）来确认该值，以获得更好的R0估计值。使用基于贝叶斯统计推断的方法来说明R的变化。第一个模型计算的R0为1.02 [置信区间（CI）为0.75-1.29]，均方根误差为7.72。指数增长率法和最大似然估计法得出的R0分别为0.93（CI为0.77-1.10）和R0为1.23（CI为0.94-1.57）。R的变化范围为0.69至2.20。通过三种不同方法计算出的斯里兰卡COVID-19的估计R0在0.93至1.23之间，并且透射率R有所降低，表明所采取的措施已实现了良好的疾病控制。指数增长率法和最大似然估计法得出的R0分别为0.93（CI为0.77-1.10）和R0为1.23（CI为0.94-1.57）。R的变化范围为0.69至2.20。通过三种不同方法计算出的斯里兰卡COVID-19的估计R0在0.93至1.23之间，并且透射率R有所降低，表明所采取的措施已实现了良好的疾病控制。指数增长率法和最大似然估计法得出的R0分别为0.93（CI为0.77-1.10）和R0为1.23（CI为0.94-1.57）。R的变化范围为0.69至2.20。通过三种不同方法计算出的斯里兰卡COVID-19的估计R0在0.93至1.23之间，并且透射率R有所降低，表明所采取的措施已实现了良好的疾病控制。