Abstract
Objective Nasopharyngeal swab (NPS) sampling has been recommended by the World Health Organization
(WHO) since the start of the COVID-19 pandemic, and real-time reverse transcription
polymerase chain reaction (RT–PCR) is used to detect SARS-CoV- 2, the causative agent
of COVID-19. This sampling technique is invasive and causes discomfort to the patient.
Saliva swabs (SSs) can be used as an alternative noninvasive method; however, there
are limited data confirming its suitability for the diagnosis of COVID-19. The aim
of this study was to test the ability to detect COVID-19 using SSs in comparison with
NPSs in the Baghdad Alkark sector.
Materials and Methods Six hundred and fifty patients were included in this study, and written informed
consent was obtained from all the study participants. Paired NPSs and SSs were collected
at the same time from each participant between days 3 and 5 after disease initiation.
SSs were taken from the sublingual area. An RT‒PCR assay was used to detect the viral
ribonucleic acid (RNA) of SARS-CoV-2 for the diagnosis of COVID-19. The chi-squared
test was used for data analysis, with p < 0.05 considered significant.
Results Out of 650 participants with suspected COVID-19 (313 males and 145 females), 313
were confirmed to be positive for COVID-19 by quantitative RT–PCR (RT‒qPCR) using
both samples. The ages ranged between 12 and 85 years, with a mean/standard deviation
(SD) of 45.45 (16.62) years. All the cases with positive results using NPSs were also
positive when SSs were used. Statistically, there was no significant difference between
the two groups (p = 0.347).
Conclusion RT‒PCR assays conducted on SSs and NPSs performed similarly, indicating that SSs
may be a safe, inexpensive diagnostic sampling method and an effective tool for population
screening. We recommend more studies to support this finding.
Keywords
diagnosis - COVID-19 - saliva swab - nasopharyngeal swab - SA
