Impact of social distancing measures on the daily number of new COVID-19 cases in Côte d’Ivoire: a retrospective cohort study (preprint)

ABSTRACT

Introduction Côte d’Ivoire is facing a second wave of the novel coronavirus disease 2019 (COVID-19). While social distancing measures (SDM) may be an option to address this wave, SDM may be devastating, especially if they have a minimal impact on the spread of COVID-19, given the other measures in place. Methods We conducted a cohort study involving cases that had occurred as at June 30, 2020. We used data from the Government’s situation reports. We established three study periods, which correspond to the implementation and easing of SDM, including a 10-day delay for test results: (1) the SDM (March 11 - May 24), (2) the no SDM (May 25 - June 21), and (3) the pseudo SDM (June 22 - July 10) periods. We compared the incidence rate during these periods using Poisson regression, with sex, age, and the average daily number of tests as covariates. Results As at July 10, there were 12,052 cases. The incidence rate was 100% higher during period 2 compared to period 1 (incidence rate ratio = 2.05, 95% confidence interval 1.75-2.41) and 25% lower during period 3 compared to period 2 (0.75 [0.66-0.86]). Conclusions The easing and subsequent reinforcement of SDM had a significant impact on the spread of COVID-19 in Côte d’Ivoire. The other mitigation measures either did not compensate for the easing of the SDM during the no SDM period or were not fully effective throughout the study periods; they should be strengthened before the SDM are reimplemented.