Quantifying Rapid Antigen Diagnostic Resource Requirements for SARS-CoV-2: A Cost-Effectiveness Analysis of Testing Strategies for Five Countries in Sub-Saharan Africa

Background: Molecular testing (PCR) is the recommended method for the diagnosis of coronavirus disease 19 (COVID-19). In low-resource settings (LRS), the availability and public health impact of these tests is constrained. Despite lower sensitivity, antigen detection rapid diagnostic tests (Ag-RDTs) could provide improved access at lower costs and quicker turnaround-time (TAT). We evaluated the optimal use of Ag-RDTs to increase testing access within TAT and reduce the cost and the number of cases missed in LRS.  Methods: We modeled estimated COVID-19 testing demand coverage based on current PCR capacity in three different epidemic phases across five African countries. We then modelled five additional testing strategies that utilized a combination of PCR and Ag-RDT.  For each strategy, epidemic phase and country, we estimated the total number of correct test results expected within a 48hr-TAT, the number of positive cases missed, corresponding costs ($12/PCR, $6/Ag-RDT), and the incremental cost-effectiveness ratios.  Findings: Across all countries and phase of epidemic, there was insufficient PCR capacity to meet the calculated required testing demand. The strategy limited to current PCR capacity was not considered cost-effective. Saturating testing demand with Ag-RDT was considered robustly cost-effective in every epidemic phase ($5-$7/additional person with a correct test result within 48hr-TAT and $50-$1000/additional case missed averted)  Interpretation: Inclusion of Ag-RDT in testing strategies is cost-effective and critical in increasing timely testing access in countries with low PCR capacity.  Funding: Supported by the Government of the Netherlands in the context of the ACT-Accelerator and USAID. Declaration of Interest: None to declare.