The impact of lockdown strategies on the basic reproductive number of coronavirus (COVID-19) cases in Saudi Arabia

Background & Objectives: In late December 2019, an outbreak of severe acute respiratory syndrome coronavirus 2 (SARS COV-2) occurred in the city of Wuhan, the capital of the Hubei province in the central part of the People’s Republic of China (Ren et al., 2020). In Saudi Arabia, the first case of COVID-19 was reported in March 2, 2020. In March 8, 2020, the Saudi authorities adopted the lockdown strategy to contain the disease. The aim of this study was to determine the effectiveness of the various phases of the lockdown strategy in Saudi Arabia and its impact on the basic reproductive number (R0) of the COVID-19 outbreak. Material and Methods: The timeline of the COVID-19 outbreak in Saudi Arabia was divided into three-time intervals. Google Mobility Community Reports (2020) was used to estimate the changes in community mobility during the various phases of the lockdown. The basic reproductive number (R0) of the COVID-19 outbreak was calculated daily using the Susceptible, Infected and Recovered (SIR) model based on the Saudi Ministry of Health (MOH) daily reports. This is a standard system to determine the spread of the virus on the basis of infection rate, quarantine rate as well as confirmation rate. The mean values of the calculated R0 during each interval were compared using one-way ANOVA test. Results: There was no statistically significant difference between the mean values of the different phases of the lockdown (P > 0.05). Moreover, mean R0 value of the second interval was 0.09 higher than the initial interval with free community mobility. Furthermore, the mean R0 values of the third interval with the full lockdown was 0.28 higher than the initial interval. Conclusion: Early implementation of lockdown strategy combined with other social distancing strategies help in containing infectious outbreaks in their early phases. Continuous assessment of such strategies’ effectiveness provides decision makers with precious information needed to justify their application when considering their economic impact