Simplified, Saliva-based PCR Testing for Greater Public Health Impact

Simplified, Saliva-based PCR Testing for Greater Public Health Impact

Abstract
Background. The COVID-19 pandemic presented an unprecedented demand for diagnostic testing. Testing was essential for identifying and isolating infected individuals, contract tracing and epidemiological surveillance for public health countermeasures, but was frequently strained by high costs, inadequate infrastructure and supply chain disruptions. To overcome these challenges, we developed a low-cost, open-source PCR test in an effort to deliver an equitable testing option. Key to this was saliva.
Methods. We simplified clinical diagnostic testing and developed ‘SalivaDirect’ through: 1) demonstrating the sensitivity of saliva for SARS-CoV-2 detection; 2) developing clear self-collection instructions; 3) negating the need for healthcare worker assisted collection; 4) eliminating collection tubes with preservatives; 5) replacing nucleic acid extraction with a simple heat and/or enzymatic step; 6) validating each protocol step with reagents and instruments from multiple suppliers; 7) demonstrating stable detection after prolonged periods at elevated temperatures; and 8) establishing a novel emergency use authorization (EUA) regulatory model. Moreover, we have recently validated this approach for the detection of influenza A/B, RSV and mpox in saliva.
Results. Since being granted EUA in August 2020, 200+ laboratories across 42 U.S. states have been designated to deploy the SalivaDirect SARS-CoV-2 protocol; more than 8 million tests have been run. SalivaDirect’s open-source, streamlined design allows laboratories to utilize existing infrastructure, thereby facilitating rapid scale up, while enabling quicker turnaround times and ensuring actionable results. Additional approaches, including unsupervised self-collection, direct-to-consumer collection kits, and pooled sample testing, increase autonomy, making it an invaluable option for numerous communities.
Conclusions. The advances in the scale and innovation in diagnostic testing throughout the COVID-19 pandemic have demonstrated what could be possible for respiratory pathogens across the board. Our extensive validation of saliva and the international implementation of SalivaDirect has demonstrated saliva as sensitive and reliable for SARS-CoV-2 detection. Importantly, this simplified approach is demonstrating applicability to other infectious diseases. Being less invasive and less resource-intensive than other sample types, saliva-based testing can lead to more equitable and sustainable testing and surveillance programs. As a result, saliva can bolster the public health response, particularly in low-resource and remote environments.