Accurate Covid-19 Serological Surveillance Using Easy-to-Collect Saliva Samples


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…saliva sampling makes it possible to frequently and easily collect and test samples from the same person to unlock the much-needed data that can be used to map the magnitude and longevity of the immune response.

A new serological assay is poised to enhance COVID-19 surveillance efforts with a simple, easy-to-collect saliva sample. “Today, Salimetrics is pleased to announce that after rigorous evaluation and validation, the Salimetrics SalivaLab will offer SARS-CoV-2 N-Protein IgG testing services to researchers for use with oral fluid samples,” says Steve Granger, Ph.D. Salimetrics Chief Scientific Officer. “The Salimetrics SARS-CoV-2 assay is being offered as a “Research Use Only (RUO)” service, providing a better method to advance our understanding of disparities in COVID-19 exposure history, risk, morbidity, and mortality.”

This new offering employs a small test volume that can be processed in conjunction with saliva samples collected for active infection diagnosis. “Data has shown that results from saliva enriched with IgG (i.e., gingival crevicular fluid, and oral mucosal transudate) match COVID-19 IgG levels measured in serum exceptionally well. These findings by Randad et al (2020) reveal the utility of oral fluid for SARS-CoV-2 antibody detection. But the potential of saliva goes further. When the duration of the immune system’s response to infection is unknown, saliva sampling makes it possible to frequently and easily collect and test samples from the same person to unlock the much-needed data that can be used to map the magnitude and longevity of the immune response. In addition, the Salimetrics SalivaLab can also process serum samples, and when tested with matched saliva samples, the combined serological data is robust and well supported by validated controls. “We realize that accessibility to trustworthy, reliable data is key in supporting this effort,” says Granger, “so it’s important that Salimetrics is available and willing to provide answers that researchers need.”

For more than 20 years, Salimetrics has championed oral fluid sampling as an alternative to traditionally invasive specimens. Since oral fluid is minimally invasive, it can be safely and frequently self-collected. These implicit advantages of oral fluid as a biospecimen make it an ideal sample in the context of the COVID-19 pandemic. Now, broad population-based seroprevalence studies of recent and past infections can begin to answer how COVID-19 hotspots spread, which individual characteristics or risk factors contribute to SARS-CoV-2 infection severity, the ratio of asymptomatic vs. symptomatic cases, and how long COVID-19 antibodies remain in circulation.

While serological assays are generally serum-based, the current model was never designed to be implemented on a massive scale. Saliva provides this opportunity. With saliva, the ideal specimen is an enriched sample collected using the SalivaBio Saliva Collection Aid – OMT (SCA-OMT), exclusively from Salimetrics. The SCA-OMT consistently provides saliva samples that have been enriched above a Total IgG level threshold. For large seroprevalence surveys, whole saliva can also be collected efficiently and effectively using the Passive Drool Collection System with the SalivaBio Saliva Collection Aid, provided an additional qualification of Total IgG level is utilized for the negative samples.

Salimetrics stands by the research community to continue to drive research forward. “We are here to help. Use our experts to refine and optimize your sample collection, handling, storage, and transportation protocols for better results,” says Supriya Gaitonde, Ph.D., Salimetrics Senior Applications Scientist. “Together we can make a difference and find the answers.”

About Salimetrics:

Salimetrics assay kits and CLIA-certified testing services are used to measure salivary analytes related to stress, behavior and development, inflammation, sleep, reproduction, health and immune function. Founded in 1998 by Douglas A. Granger, Ph.D., Salimetrics, LLC supports CROs, pharmaceuticals, academic researchers and the immunodiagnostic industry around the world with innovative immunoassay products, non-invasive saliva collection methods, and laboratory testing services.

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