Source of data
This is secondary data gotten from a diagnostic evaluation of the performance characteristics of novel rapid diagnostic tests for SARS-CoV-2 compared to RT-PCR which was carried on consenting individuals aged 21 years or older who presented to any of eight COVID-19 testing sites across the Centre Region of Cameroon between June and August 2020.
Demographic and clinical information was collected from participants including self-reported age, race, ethnicity, and gender. Brief clinical history and case management pertaining to the suspected SARS-CoV-2 infection was recorded, including duration of symptoms, date of symptom onset, date of exposure/infection (if known), symptoms on admission/presentation, disease stage (mild, severe, or critical according to WHO classification), date of admission and discharge (for hospitalized patients), and outcome. At this initial visit (Visit 1), participants were invited return for at least two follow-up visits. Visit 2 was planned for seven days after Visit 1 and Visit 3 was planned within 10–14 days after Visit 1.
At all visits, we collected whole blood by peripheral venepuncture into EDTA-coated and red-top vacutainers. Nasopharyngeal swabs were collected using sterile technique compliant with rigorous infection control guidelines. Nasopharyngeal swab samples for PCR testing were transported in virologic media and stored at the National Laboratory of Public Health at -20° C.
The Innovita (Innovita [Tangshan] Biological Technology Co., Ltd., Beijing, China) test, provided by the Ministry of Health, was the antibody based RDT performed on all participants.
RT-PCR testing was performed at Cameroon’s National Public Health Laboratory, where two different protocols were used to amplify SARS-CoV-2 RNA from nasopharyngeal swab samples: an automated extraction protocol and a manual extraction protocol (9). RNA was extracted using a kit for nucleic acid isolation and purification reagent (DAAN Gene, Sun Yat-sen University). Abbott m2000 (Abbot laboratories, Illinois, USA) was then employed and amplification was completed in real-time thermocyclers. The automated extraction protocol was performed using ABBOTT m2000 Real-time SARS-CoV-2 assay. The manual extraction protocol was performed using New RNA detection Coronavirus 2019 Decentralization (SARS-CoV-2; Sun Yat-sen University Protocol), which involves real-time amplification using Taqman probes of purified RNA and was carried out using an ABI 7500 thermocycler (Applied Biosystems, Foster City, USA) following manufacturer’s instructions.
Statistical analysis
Data was entered into Microsoft excel spreadsheets and analysis was done using R software.
Tables were used to present data. Qualitative data was described as proportions while quantitative data was described with means and accompanying ranges. Significance was set at p < 0.05.