AbstractIn Africa, while most countries report some COVID-19 cases, the fraction of reported patients is low, with about 20 000 cases compared to the more than 2.3 million cases reported globally as of April 18, 2020. Few African countries have reported case numbers above one thousand, with South Africa reporting 3 034 cases being hit hardest in Sub-Saharan Africa. Several African countries, especially South Africa, have already taken strong non-pharmaceutical interventions that include physical distancing, restricted economic, educational and leisure activities and reduced human mobility options. The required strengths and overall effectiveness of such interventions, however, are debated because of simultaneous but opposing interests in most African countries: strongly limited health care capacities and testing capabilities largely conflict with pressured national economies and socio-economic hardships on the individual level, limiting compliance to intervention targets. Here we investigate implications of interventions on the COVID-19 outbreak dynamics, focusing on South Africa before and after the national lockdown enacted on March 27, 2020. Our analysis shows that initial exponential growth of existing case numbers is consistent with doubling times of about 2.5 days. After lockdown, the growth remains exponential, now with doubling times of 18 days, but still in contrast to subexponential growth reported for Hubei/China after lockdown. Moreover, a scenario analysis of a computational data-driven agent based mobility model for the Nelson Mandela Bay Municipality (with 1.14 million inhabitants) hints that keeping current levels of intervention measures and compliance until the end of April is of insufficient length and still too weak, too unspecific or too inconsistently complied with to not overload local intensive care capacity. Yet, enduring, slightly stronger, more specific interventions combined with sufficient compliance may constitute a viable option for interventions for regions in South Africa and potentially for large parts of the African continent.EXECUTIVE SUMMARYEvidence before this studySeveral studies have analyzed the ongoing outbreak of the Corona Virus Disease 2019 (COVID-19) in China and several European countries. However, conditions in African countries are vastly different and often fragile, with conflicting limitations of both the health care system and socio-economic conditions, posing difficult challenges for decisions about enacting and lifting interventions. These countries are currently in the early stages of the outbreak and have been reporting a small but rapidly increasing number of patients diagnosed with COVID-19. Several countries have taken different intervention measures to counter a large-scale COVID-19 outbreak. In particular, in South Africa, with the largest number of cases in Sub-Saharan Africa, case numbers are known to less rapidly increase after national lockdown on March 27, 2020.Added value of this studyThis study reports a quantitative analysis of the case number dynamics reported by the World Health Organization and Johns Hopkins University until including April 18, 2020, both for Africa overall and South Africa specifically, before and after national lockdown. It also reports and analyzes results of an agent-based mobility simulation for the Nelson Mandela Bay Municipality, South Africa (1.14 million inhabitants). This case study relies on detailed large-scale mobility survey data of about 10% of the population and on estimates of the fractions by which interventions decrease specific activities. The simulational data on outbreak dynamics thus provide qualitative order of magnitude estimates of trends consistent with past data. Combined, both analyses may help to better understand the implications of interventions on and estimate the dynamics of the number of (critically) infected patients.Implications of all the available evidenceThe results suggest that current interventions are not yet sufficient to contain a larger-scale outbreak. Interventions slightly stronger than those implemented today or a higher degree of compliance to the enacted lockdown, in combination with longer-lasting measures than currently announced for South Africa may help bound the case numbers such that the number of critical patients remains at or below (and does not massively overburden) the local capacity of intensive care units. Strategies for strengthening or lifting interventions should be advised by advanced data analytics and predictive modeling estimates, for instance for evaluating necessary time intervals and required levels of interventions. Overall, the study points to a potentially viable chance for effective non-pharmaceutical countermeasures against COVID-19 epidemics in South Africa, with suggestions for Health Policy for large parts of the African continent and, generally, disadvantaged countries and regions.
Analyzing the contributions of transdisciplinary research to the global sustainability agenda in African cities
