Avaliação molecular da saliva como meio de detecção do SARS-CoV-2

Abstract

SARS-CoV-2, which causes Covid-19, was first identified in Wuhan, Hubei Province, China, and is now spreading on a global scale. Diagnosis is performed by real-time reverse transcription polymerase chain reaction (RT-qPCR) by nasopharyngeal swab collection (NFS). Due to high testing demand and low supplies of collection materials, the need for alternative methods to facilitate accurate universal Covid-19 screening and pandemic control is highlighted. Thus, this study aimed to evaluate the molecular efficiency of saliva as a means of detecting SARS-CoV-2 in health professionals and patients in the surgical circuit of Hospital Universitário Lauro Wanderley. For this, 365 collections of SNF and saliva samples were performed, which were extracted and quantified in concentration. Identification was performed by RT-qPCR. The results showed that of the 365 samples analyzed, 45 (12.3%) had detection in at least one type of sample and the majority were 27 (60%) asymptomatic. 21 (46.7%) samples were positive for SNF and saliva, while 14 (31.1%) were positive for SNF samples only and 10 (22.2%) were positive for saliva samples only. The concentration of saliva samples was 28.6 and 30.4 ± SD for 7.6 and 8.38 ± SD of SNF. Purity ranged from 1.81 and 0.3 ± SD in saliva to 1.82 and 0.25 ± SD in SNF. Using SNF samples as the gold standard of reference, the sensitivity and specificity of saliva were 60% 97%, while positive and negative predictive values were 68% and 96%, respectively. The accuracy was 93.0% and the Kappa coefficient was 0.596. In conclusion, the results obtained in the self-collection of pure saliva are similar compared to SNF samples, being viable to be used in the detection of SARS-CoV-2.