Comparative evaluation of saliva and nasopharyngeal swab for SARS-CoV-2 detection using RT-qPCR among COVID-19 suspected patients at Jigjiga, Eastern Ethiopia.

Nasopharyngeal swab (NPS) remains the recommended sample type for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) diagnosis. However, the collection procedure causes discomfort and irritation to the patients, lowering the quality of the sample and exposing healthcare workers to risk. Furthermore, there is also a shortage of flocked swabs and personnel protective equipment in low-income settings. Therefore, this necessitates an alternative diagnostic specimen. The purpose of this study was to evaluate the performance of saliva against NPS for SARS-CoV-2 detection using RT-qPCR among COVID-19 suspected patients at Jigjiga, Eastern Ethiopia. Comparative cross-sectional study was conducted from June 28 to July 30, 2022. A total of 227 paired saliva and NPS samples were collected from 227 COVID-19 suspected patients. Saliva and NPS samples were collected and transported to the Somali Regional Molecular Laboratory. Extraction was conducted using DaAn kit (DaAn Gene Co., Ltd China). Veri-Q RT-qPCR was used for amplification and detection (Mico BioMed Co, Ltd, Republic of Korea). The data were entered into Epi-data version 4.6 and analyzed using SPSS 25. McNemar's test was used to compare the detection rate. Agreement between NPS and saliva was performed using Cohen's Kappa. The mean and median of cycle threshold values were compared using paired t-tests and the correlation between cycle threshold values was measured using Pearson correlation coefficient. P value < 0.05 was considered statistically significant. The overall positivity rate of SARS-CoV-2 RNA was 22.5% (95% CI 17-28%). Saliva showed higher sensitivity (83.8%, 95% CI, 73-94.5%) than NPS (68.9%, 95% CI 60.8-76.8%). The specificity of saliva was 92.6% (95% CI, 80.6% - 100%) compared to NPS (96.7%, 95% CI, 87% - 100%). The positive, negative, and overall percent agreement between NPS and saliva was 83.8%, 92.6%, and 91.2% respectively (κ = 0.703, 95% CI 0.58-0.825, P = 0.00). The concordance rate between the two samples was 60.8%. NPS showed a higher viral load than saliva. There was low positive correlation between the cycle threshold values of the two samples (r = 0.41, 95% CI -1.69 to -0.98, P >0.05). Saliva showed a higher detection rate for SARS-CoV-2 molecular diagnosis than NPS and there was significant agreement between the two specimens. Therefore, saliva could be suitable and easily obtainable alternative diagnostic specimen for SARS-CoV-2 molecular diagnosis.

Tahir B ，Weldegebreal F ，Ayele F ，Ayana DA ... -  《PLoS One》

Diagnostic Performance of Self-Collected Saliva Versus Nasopharyngeal Swab for the Molecular Detection of SARS-CoV-2 in the Clinical Setting.

Uddin MKM ，Shirin T ，Hossain ME ，Alam AN ，Ami JQ ，Hasan R ，Miah M ，Shaly NJ ，Ahmed S ，Rahman SMM ，Rahman M ，Banu S ... -  《Microbiology Spectrum》

Diagnostic Performance and Tolerability of Saliva and Nasopharyngeal Swab Specimens in the Detection of SARS-CoV-2 by RT-PCR.

Ahti J ，Österback R ，Keskitalo A ，Mokkala K ，Vidbäck S ，Veikkolainen V ，Vuorinen T ，Peltola V ，Hakanen AJ ，Waris M ，Laine M ... -  《Microbiology Spectrum》

Saliva as alternative to naso-oropharyngeal swab for SARS-CoV-2 detection by RT-qPCR: a multicenter cross-sectional diagnostic validation study.

Saliva has been demonstrated as feasible alternative to naso-oropharyngeal swab (NOS) for SARS-CoV-2 detection through reverse transcription quantitative/real-time polymerase chain reaction (RT-qPCR). This study compared the diagnostic agreement of conventional NOS, saliva with RNA extraction (SE) and saliva without RNA extraction (SalivaDirect) processing for RT-qPCR in identifying SARS-CoV-2. All techniques were also compared, as separate index tests, to a composite reference standard (CRS) where positive and negative results were defined as SARS-CoV-2 detection in either one or no sample, respectively. Of 517 paired samples, SARS-CoV-2 was detected in 150 (29.01%) NOS and 151 (29.21%) saliva specimens. The saliva-based tests were noted to have a sensitivity, specificity and accuracy (95% confidence interval) of 92.67% (87.26%, 96.28%), 97.55% (95.40%, 98.87%) and 96.13% (94.09%, 97.62%), respectively, for SE RT-qPCR and 91.33% (85.64%, 95.30%), 98.91% (97.23%, 99.70%) and 96.71% (94.79%, 98.07%), respectively, for SalivaDirect RT-qPCR compared to NOS RT-qPCR. Compared to CRS, all platforms demonstrated statistically similar diagnostic performance. These findings suggest that both conventional and streamlined saliva RT-qPCR are at least non-inferior to conventional NOS RT-qPCR in detecting SARS-CoV-2.

Tee ML ，Abrilla AA ，Tee CA ，Dalmacio LMM ，Villaflor VJP 3rd ，Abubakar AA ，Tagayuna PY ，Aquino SSC ，Bernardo VAL 6th ，Matias RR ... -  《Scientific Reports》

Saliva as a testing specimen with or without pooling for SARS-CoV-2 detection by multiplex RT-PCR test.

Sun Q ，Li J ，Ren H ，Pastor L ，Loginova Y ，Madej R ，Taylor K ，Wong JK ，Zhang Z ，Zhang A ，Lu CM ，Sha MY ... -  《PLoS One》