ABSTRACT
Digital tools can support community-based decentralized testing initiatives to broaden access to COVID-19 diagnosis, especially in high-transmission settings. This operational study investigated the use of antigen-detecting rapid diagnostic tests (Ag-RDTs) for COVID-19 combined with an end-to-end digital health solution, in three taxi ranks in Johannesburg, South Africa. Members of the public were eligible if they were aged ≥18 years, could read, and had a cellphone. Over 15,000 participants, enrolled between June and September 2021, were screened for COVID-19 risk factors. A digital risk questionnaire identified 2061 (13%) participants as moderate risk and 2987 (19%) as high risk, based on symptoms and/or recent exposure to a known case. Of this group referred for testing, 3997 (79%) received Ag-RDTs, with positivity rates of 5.1% in the "high-risk" group and 0.8% in the "moderate-risk" group. A subset of 569 randomly selected participants received additional PCR testing. Sensitivity of the Ag-RDT in this setting was 40% (95% CI: 30.3%, 50.3%); most false negatives had high cycle threshold values (>25), hence low viral loads. Over 80% of participants who tested positive completed a 2-week phone-based follow-up questionnaire. Overall, the digital tool combined with Ag-RDTs enhanced community-based decentralized COVID-19 testing service delivery, reporting and follow-up.
ABSTRACT
BACKGROUND: SARS-CoV-2 is a novel coronavirus discovered in December 2019 and is currently the cause of the global COVID-19 pandemic. A critical aspect of fighting this pandemic is to obtain accurate and timely test results so that patients who have tested positive for COVID-19 can be identified and isolated to reduce the spread of the virus. Research has shown that saliva is a promising candidate for SARS-CoV-2 diagnostics because its collection is minimally invasive and can be reliably self-administered. However, little research has been conducted on saliva testing and SARS-CoV-2 self-sampling (SARS-CoV-2SS) in Sub-Saharan Africa. OBJECTIVE: The primary objective of this study is to comparatively evaluate the clinical sensitivity and specificity of nasal and oral samples self-collected by individuals for SARS-CoV-2 testing against a reference method involving sample collection and testing by a health care professional. The secondary objectives of this study are to evaluate the usability of nasal self-sampling and saliva self-sampling as a sample collection method for SARS-CoV-2 diagnostic testing by using failure mode and error assessment. METHODS: Participants will be recruited from the general population by using various methods, Participants will be screened progressively as they present at the clinical trial sites as well as in primary health care catchment areas in the inner city of Johannesburg, South Africa. In the event that recruitment numbers are low, we will use a mobile van to recruit participants from outlying areas of Johannesburg. We aim to enroll 250 participants into this study in approximately 6 weeks. Two sample types-a self-administered nasal swab and a self-administered saliva sample-will be collected from each participant, and a health care professional will collect a third sample by using a nasopharyngeal swab (ie, the standard reference method). RESULTS: This protocol has been approved by the University of the Witwatersrand Human Research Ethics Committee on July 31, 2020 (Protocol number EzCov003). As of May 13, 2021, 120 participants have been enrolled into the study. CONCLUSIONS: SARS-CoV-2SS may offer many benefits to individuals, by allowing for initial self-identification of symptoms and collection of samples without involving third parties and potential risk of infection provided the sample can be safely processed via a collection system. The results of this study will provide preliminary data on the acceptability, feasibility, and usability of SARS-CoV-2SS among the general population for its future implementation. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/24811.