Evaluation of the effect of border closure on COVID-19 incidence rates across nine African countries: an interrupted time series study

BACKGROUND: Border closure is one of the policy changes implemented to mitigate against coronavirus disease 2019 (COVID-19). We evaluated the effect of border closure on the incidence rate of COVID-19 across nine African countries. METHODS: An interrupted time series analysis was used to assess COVID-19 incidence rates in Egypt, Tunisia, Democratic Republic of the Congo (DRC), Ethiopia, Kenya, Ghana, Nigeria, Senegal and South Africa (SA). Data were collected between 14 February and 19 July 2020 from online data repositories. The linear trend and magnitude of change were evaluated using the itsa function with ordinary least-squares regression in Stata with a 7-d deferred interruption point, which allows a period of diffusion post-border closure. RESULTS: Overall, the countries recorded an increase in the incidence rate of COVID-19 after border closure. However, when compared with matched control groups, SA, Nigeria, Ghana, Egypt and Kenya showed a higher incidence rate trend. In contrast, Ethiopia, DRC and Tunisia showed a lower trend compared with their controls. CONCLUSIONS: The implementation of border closures within African countries had minimal effect on the incidence of COVID-19. The inclusion of other control measures such as enhanced testing capacity and improved surveillance activities will reveal the effectiveness of border closure measures.