ABSTRACT
BackgroundEffective management of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) requires large-scale testing. Collection of nasopharyngeal swab (NPS) by healthcare workers (HCW) is currently used to diagnose SARS-CoV-2, which increases the risk of transmission to HCWs. Self-administered saliva and buccal swabs are convenient, painless and safe alternative sample collection methods. MethodsA cross-sectional single centre study was conducted on 42 participants who were tested positive for SARS-CoV-2 via NPS within the past 7 days. A self-collected saliva and buccal swab and a HCW-collected NPS were obtained. Real-time polymerase chain reaction (RT-PCR) was performed and cycle threshold (CT) values were obtained. Positive percent agreement (PPA), negative percent agreement (NPA) and overall agreement (OA) were calculated for saliva and buccal swabs, as compared with NPS. ResultsAmong the 42 participants, 73.8% (31/42) tested positive via any one of the 3 tests. With reference to NPS, the saliva test had PPA 66.7%, NPA 91.7% and OA 69.0%. The buccal swab had PPA 56.7%, NPA 100% and OA 73.8%. Presence of symptoms improved diagnostic accuracy. There was no statistically significant association between CT values and duration of symptom onset within the first 12 days of symptoms for all three modalities. ConclusionSelf-collected saliva tests and buccal swabs have only moderate agreement with HCW-collected NPS swabs. Primary screening for SARS-CoV-2 may be performed with a saliva test or buccal swab, with a negative test warranting a confirmatory NPS to avoid false negatives. This combined strategy minimizes discomfort and reduces the risk of spread to the community and HCWs.
ABSTRACT
The presence of high SARS-coronavirus 2 (SARS-CoV-2) titres in saliva may result in transmission of the virus and increase the risk of COVID-19 infection. This is particularly important as significant amounts of aerosols are generated during dental procedures, posing risk to dental care personnel and patients. Thus, reducing the titres of SARS-CoV-2 in the saliva of infected patients could be one of the key approaches to reduce the risk of COVID-19 transmission during dental procedures. In this randomised control trial, the efficacy of three commercial mouth-rinse viz. povidone-iodine (PI), chlorhexidine gluconate (CHX) and cetylpyridinium chloride (CPC), in reducing the salivary SARS-CoV-2 viral load in COVID-19 positive patients were compared with water. A total of 36 COVID-19 positive patients were recruited, of which 16 patients were randomly assigned to four groups-- PI group (n=4), CHX group (n=6), CPC group (n=4) and water as control group (n=2). Saliva samples were collected from all patients at baseline and at 5 min, 3 h and 6 h post-application of mouth-rinses/water. The samples were subjected to SARS-CoV-2 RT-PCR analysis. The fold change of Ct values were significantly increased in CPC group at 5 minutes and 6 h time points (p<0.05), while it showed significant increase at 6 h time point for PI group (p<0.01). Considering Ct values as an indirect method of arbitrarily quantifying the viral load, it can be postulated that CPC mouth-rinse can decrease the salivary SARS-CoV-2 levels within 5 minutes of use, compared to water rinsing. The effect of decreasing salivary load with CPC and PI mouth-rinsing was observed to be sustained at 6 h time point. Within the limitation of the current study, it can be concluded that use of CPC and PI formulated commercial mouth-rinses, with its sustained effect on reducing salivary SARS-CoV-2 level, may be useful as a pre-procedural rinse to help reduce the transmission of COVID-19.