Modelling COVID-19 transmission in Africa: countrywise projections of total and severe infections under different lockdown scenarios

Abstract

ObjectivesAs of 13 January 2021, there have been 3 113 963 confirmed cases of SARS-CoV-2 and 74 619 deaths across the African continent. Despite relatively lower numbers of cases initially, many African countries are now experiencing an exponential increase in case numbers. Estimates of the progression of disease and potential impact of different interventions are needed to inform policymaking decisions. Herein, we model the possible trajectory of SARS-CoV-2 in 52 African countries under different intervention scenarios.DesignWe developed a compartmental model of SARS-CoV-2 transmission to estimate the COVID-19 case burden for all African countries while considering four scenarios: no intervention, moderate lockdown, hard lockdown and hard lockdown with continued restrictions once lockdown is lifted. We further analysed the potential impact of COVID-19 on vulnerable populations affected by HIV/AIDS and tuberculosis (TB).ResultsIn the absence of an intervention, the most populous countries had the highest peaks in active projected number of infections with Nigeria having an estimated 645 081 severe infections. The scenario with a hard lockdown and continued post-lockdown interventions to reduce transmission was the most efficacious strategy for delaying the time to the peak and reducing the number of cases. In South Africa, projected peak severe infections increase from 162 977 to 2 03 261, when vulnerable populations with HIV/AIDS and TB are included in the analysis.ConclusionThe COVID-19 pandemic is rapidly spreading across the African continent. Estimates of the potential impact of interventions and burden of disease are essential for policymakers to make evidence-based decisions on the distribution of limited resources and to balance the economic costs of interventions with the potential for saving lives.

Impact of COVID-19 on Tuberculosis Case Detection and Treatment Outcomes in Sierra Leone

“…Our observations are consistent with recent studies from Nigeria, Ethiopia, Malawi, Zimbabwe and elsewhere in SSA [14][15][16][17][18][19]. While these findings have been attributed largely to the direct effects of the COVID-19 lockdowns, Thakur et al and others [15][16][17] have suggested that other factors unrelated to the COVID-19 pandemic may be contributory.…”

A SIRD model applied to COVID-19 dynamics and intervention strategies during the first wave in Kenya

“…The basic reproduction number is 2.76 which is consistent with results from other computations, e.g. [23].…”

“…The surface is bounded by curves defined by constant values of mitigation and relaxation percentages. We have already seen that hard lockdown was defined as mitigation of 44% and moderate lockdown as mitigation of 25% [23]; it is therefore reasonable to start with mitigation percentages in the range (25, 50). Relaxation techniques applied after mitigation are designed to increase the transmission rate, preferably to 80% - 90% of the pre-mitigation transmission.…”

“…Once the value of c is estimated, it can be described in simple terms for public health implementation. For instance, two intervention scenarios are mentioned in [23], namely: moderate lockdown , regarded as the intervention which reduces transmission by 25% during lockdown followed by transmission at 90% of the pre-lockdown value; and hard lockdown , regarded as the intervention which reduces transmission by 44% during lockdown followed by transmission at 90% of the pre-lockdown value. In terms of our formulation, moderate lockdown is equivalent to mitigation with c = 0.25 followed by relaxation with c = − 2.6 while hard lockdown is equivalent to mitigation with c = 0.44 followed by relaxation with c = − 1.05.…”

“…In the deterministic model, the population is usually divided into various compartments, namely Susceptible (S), infectious (I), Recovered (R) and Dead (D). Some models use all the compartments and are labelled SEIRD [21, 22]] while other models omit the Dead compartment and are SEIR [15, 23] or omit the exposed compartment and are SIRD [24 - 26] or end up with the basic SIR formulation by omitting the Exposed and Dead compartments [20, 27]. Irrespective of the number of compartments used above, models can be modified to include additional compartments like hospitalised, symptomatic, asymptomatic, among others [28 - 33].…”