ABSTRACT
Background:
In
resource-poor countries,
antigen-based rapid tests (Ag-RDTs) performed at
primary healthcare and
community settings improved access to
SARS-CoV-2 diagnostics. However, the technical skills and
biosafety requirements inherent to nasopharyngeal and oropharyngeal (OP) specimens limit the scale-up of
SARS-CoV-2 testing. The collection of nasal-swabs is programmatically viable, but its performance has not been evaluated in
resource-poor settings.
Methods:
We first evaluated the performance of SteriPack
self-collected nasal swabs for the
detection of
SARS-CoV-2 by
real-time PCR in 1498 consecutively enrolled
patients with suspected
infection. Next, we evaluated the clinical performance of three nasal swab-based Ag-RDTs against
real-time PCR on OP specimens.
Results:
The
sensitivity of nasal swabs was 80.6% [95% CI 75.3−85.2%] compared to OP specimens. There was a good correlation (r = 0.58; p < 0.0001) between Ct values of 213 positive cases obtained using nasal and OP swabs. Our findings show sensitivities of 79.7% [95% CI 73.3−85.1%] for Panbio COVID-19 Ag-RDT, 59.6% [95% CI 55.2−63.8%] for COVIOS Ag-RDT, and 78.0% [95% CI 73.5−82.0%] for the LumiraDx
SARS-CoV-2 Ag-RDT.
Conclusions:
In our setting, the COVIOS Ag-RDT did not meet
WHO requirements. Nasal swab-based Ag-RDTs for
SARS-CoV-2 detection constitute a viable and accurate diagnostic option in
resource-poor settings.