Rapid and accurate viral detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical in controlling outbreaks in community and health care settings , to identify both symptomatic and asymptomatic patients. Nasopharyngeal swabs (NPSs) and oropharyngeal swabs (OPSs) are two of the most common upper respiratory tract specimen types recommended for SARS-CoV-2 diagnostic testing.
The limited inventory of protective gear and testing supplies has prompted evaluation of alternate sample types that can be obtained with minimized HCW exposure and which do not require specialized collection materials, including swabs and viral transport media. Oral rinses and saliva samples in patients are also being tested, to determine the reliability of self-collected ORs and posterior oropharyngeal saliva as alternative sample types for the detection of SARSCoV-2 RNA in Health care workers.
In a study conducted at Memorial Sloan Kettering Cancer Center (MSKCC) in New York City , NPS and OPS samples were collected using flocked swabs and placed in viral transport media. For saliva specimens, HCWs were first asked to swallow and then bring up saliva from the back of the throat and spit at least 3.0 mL of saliva into an empty sterile container. For oral rinses, HCWs were asked to place 10 mL of sterile water in their mouth and with mouth closed, swish for 15 seconds, without gargling and spit the water in a sterile container. NPSs and OPSs were collected by nurses at test sites who were trained in the swab technique, whereas saliva and mouth wash samples were self-collected.
SARS-CoV-2 RNA detection from saliva was found to be superior to oropharyngeal swabs and equivalent to nasopharyngeal swabs . While ,oral rinses were suboptimal for the diagnosis of SARS-CoV-2 when compared with nasopharyngeal swab.
To summarize, studies revealed that , SARS-CoV-2 RNA detection in oral rinses is not a suitable alternative to swab methods, whereas , undiluted saliva was shown to be a better sample for self-collection . These results collectively suggest that saliva is an acceptable alternative to NPSs for SARS-CoV-2 RNA detection by RT-PCR, with the distinct advantages of being broadly deployable and obviating pervasive testing supply shortages.
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