Evaluating saliva for SARS-CoV-2 detection: A practical alternative.

Accurate and rapid detection of SARS-CoV-2 is critical for controlling the spread of COVID-19, particularly among asymptomatic carriers. This study evaluates saliva as a viable alternative to nasopharyngeal swabs (NPS) for SARS-CoV-2 detection using real-time RT-PCR and rapid antigen testing (RAT). A total of 201 paired NPS and saliva samples were collected and analyzed. Saliva-based RT-PCR demonstrated 100 % (95 % CI, 94.64 % to 100 %) sensitivity and 97.10 % (95 % CI, 92.74 % to 99.2 %) specificity, with an overall accuracy of 98.05 % (95 % CI, 95.44 % to 99.47 %), closely aligning with NPS results. Similarly, saliva-based RAT exhibited comparable diagnostic performance to NPS-based RAT, with sensitivity and specificity of 100 % (95 % CI 90.51-100 %) and 99.39 % (95 % CI 96.67-99.98 %) respectively. When compared to the gold standard NPS real-time RT-PCR, the sensitivity of RAT using saliva and NPS samples was found to be 69.07 % (95 % CI, 58.88 % to 78.08 %) and 69.79 % (95 % CI, 59.57 % to 78.75 %), respectively. Notably, for cases with cycle threshold (Ct) values ≤30, saliva RAT achieved 97.30 % (95 % CI, 85.84 % to 99.93 %) sensitivity, highlighting its effectiveness in detecting infectious cases. Therefore, saliva offers a practical alternative to NPS for large-scale screening, particularly in resource-limited settings, due to its non-invasive nature, ease of self-collection, and high diagnostic accuracy.