The Contribution of Rapid Antigen Tests to the Diagnosis of Active SARS-CoV-2 Infection in Limited Resources Settings, Democratic Republic of the Congo

In the context of a rapidly spreading pandemic, early detection of active infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains essential to break the chain of transmission and limit associated complications. In the Democratic Republic of the Congo (DRC), access to nucleic acid amplification tests (NAATs), such as RT-PCR, remains limited due to logistical, technical, and financial constraints. The introduction of rapid antigen diagnostic tests (RATs) represented a major advance in strengthening diagnosis. We conducted a descriptive cross-sectional study in Kinshasa to assess the operational and epidemiological contribution of RATs in detecting active SARS-CoV-2 infection. Two approved antigen tests (Panbio™ from Abbott and Standard Q™ from SD Biosensor), validated by the World Health Organization (WHO), the High Authority of Health (HAH) internationally and locally by the Institut National de Recherche Biomédicale (INRB). A total of 111,278 people suspected of infection were tested during the study period. Of these, 56,846 (51.1%) were diagnosed by RT-PCR, with a positivity rate of 30.2%, while 54,432 (48.9%) were tested by RATs, with a positivity rate of 16.8%. The male gender represented 59 780 (53,7%) and the female gender 51 498 (46,3%), with the estimated mean age at 36.9±15.9 years. The age group ≤ 21 years had the highest rate (19.1%), with a tendency for positivity to increase with age. Females had a slightly higher positivity rate than males (17.1% vs. 16.4%). All Health Zones in Kinshasa had deployed RATs, with the Barumbu Health Zone showing the highest positivity rate (37.8%). Fever (≥ 38°C) was the symptom most frequently associated with RATs positivity (16.5%). All other symptoms, including close contact with a confirmed case, showed a significant association with positivity, with the exception of cough and dyspnea. RATs played a key role in the detection of SARS-CoV-2 during the third and fourth epidemic waves, complementing RT-PCR. These results highlight the relevance of their use in resource-limited settings to improve rapid detection and guide response strategies to emerging or re-emerging respiratory epidemic threats.