Independent Evaluation of Four SARS-CoV-2 Antigen Rapid Tests Against qRT-PCR in Niger

Reliable, decentralized SARS-CoV-2 testing was a major challenge during the COVID-19 pandemic, particularly in low- and middle-income countries with limited molecular diagnostic capacity. We independently evaluated four commercial antigen rapid diagnostic tests (Ag-RDTs), including one manufactured in Africa, under routine field conditions in Niger. Between July 2021 and September 2023, four prospective evaluations were conducted among symptomatic patients presenting within seven days of symptom onset at two health facilities in Niamey. The STANDARD Q nasopharyngeal, Panbio nasopharyngeal, Panbio nasal, and SAYTU nasal Ag-RDTs were compared with qRT-PCR as the reference standard. Overall, 956 patients were enrolled, including 422 (44.1%) qRT-PCR-positive cases. Sensitivity ranged from 75.0% to 85.7%, with the highest performance observed for the Panbio nasopharyngeal test (85.7%), followed by the SAYTU nasal test (80.1%), whereas specificity exceeded 95% for all assays. Sensitivity increased in specimens with high viral RNA concentration. Only the Panbio nasopharyngeal test met the World Health Organization performance criteria (sensitivity ≥80% and specificity ≥97%). Nevertheless, the other three Ag-RDTs, including the Africa-manufactured SAYTU assay, may support screening in settings with limited molecular testing capacity, provided that negative results in symptomatic patients are confirmed by qRT-PCR.