Containment of the COVID19 pandemic relies on mass screening to allow rapid identification and isolation of cases to break transmission chains. The reference diagnostic method is based on detection of viral genomes by PCR on a nasopharyngeal swab sample (NPS).
However, the pandemic has generated a very high demand causing a shortage of specific swabs and difficulties in the supply of reagents and consumables. Nasopharyngeal sampling requires skilled personnel, and is sometimes poorly accepted by patients. These issues can reduce the quality of sampling and therefore the sensitivity of the test. This strategy also requires sending samples to specialized laboratories, generating a delay in providing results.
New diagnostic approaches on saliva samples are being developed allowing 1) an easier sampling procedure and 2) a diagnostic technique that can be performed in point-of-care.
Previous evaluations suggest that these approaches have a lower sensitivity than the reference strategy (PCR on NPS), around 50 to 90% depending on the technique used.
Despite lower sensitivity compared to the reference strategy, the investigators hypothesize that detection of SARS-CoV2 on saliva samples will improve the performance of the screening program by considerably increasing the number of individuals tested in shorter times.
The main objective of the study is to evaluate, for the detection of SARS-CoV-2 infection, the performance of various alternative virological diagnostic strategies on saliva samples, in comparison with the reference technique (RT-PCR on NPS).
The primary endpoint of the study is positivity of the standard technique (RT-PCR on NPS) for the SARS-CoV-2 virus. The result of the alternative strategies on a saliva sample will be considered as positive or negative according to criteria specific to each of them and compared to the result of the reference technique to estimate their respective sensitivity.
The secondary objectives are to compare the diagnostic performances of RT-PCR on saliva versus RT-PCR on NPS, the diagnostic performances of alternative techniques on saliva versus RT-PCR on saliva, to evaluate the acceptability of the saliva self-sampling and the cost-effectiveness of new diagnostic strategies compared to the reference technique.
The study will include adults and children in whom a NPS is performed for SARS-CoV-2 screening. After informed consent, participants will be asked to provide a saliva sample before nasopharyngeal sampling. Both samples will be analyzed in parallel. The analytical performance of each technique will be assessed, centrally or delocalised, depending on the feasibility of the techniques and according to the advice of the scientific board. The analyzes will be carried out by a team of technicians specifically recruited for the study. All samples collected will be stored in a centralized in a biobank.
