Quick and cheap saliva-based Covid-19 test developed by Yale gets FDA nod, can boost the US’s testing capacity

The method does not need any special type of swab or collection device, and a saliva sample can be collected in any sterile container


                            Quick and cheap saliva-based Covid-19 test developed by Yale gets FDA nod, can boost the US’s testing capacity
(Getty Images)

An affordable saliva-based laboratory diagnostic test developed by researchers at the Yale School of Public Health to determine whether someone is infected with Covid-19 has been granted an emergency use authorization by the US Food and Drug Administration (FDA). The test, which uses a new method of processing saliva samples when testing for coronavirus infection, could greatly expand testing capacity in the US, said experts. Testing for Covid-19 has been a major stumbling block in the fight against the pandemic in the US, with long delays and shortages of testing.

Called SalivaDirect, the method does not require any special type of swab or collection device, and a saliva sample can be collected in any sterile container. The method is highly sensitive and yields similar outcomes as nasal swabbing, reveal results. “SalivaDirect is simpler, less expensive, and less invasive than the traditional method for such testing, known as nasopharyngeal (NP) swabbing. Results so far have found that SalivaDirect is highly sensitive and yields similar outcomes as NP swabbing,” explain Yale scientists. The method is being further validated as a test for asymptomatic individuals through a program that tests players and staff from the National Basketball Association (NBA). With the FDA’s emergency use authorization, the testing method is immediately available to other diagnostic laboratories that want to start using the new test, which can be scaled up quickly for use across the nation in the coming weeks. 

Yale researchers said that the test costs only a couple dollars for reagents, and therefore, they expect labs to charge only about $10 per sample. The diagnostic test can yield results in under three hours, and about 90 samples can be tested at once. “The SalivaDirect test for rapid detection of SARS-CoV-2 is yet another testing innovation game-changer that will reduce the demand for scarce testing resources,” said Admiral Brett P Giroir, assistant secretary for health and Covid-19 testing coordinator. According to the Yale research team, some experts have said that up to 4 million coronavirus tests are needed per day in the US and SalivaDirect provides one pathway toward that goal. “Using SalivaDirect, our lab can double our testing capacity,” said Professor Chen Liu, chair of Yale Pathology, who oversaw the clinical validation of the study. 

Nathan Grubaugh, assistant professor at Yale School of Public Health, who spearheaded the development of SalivaDirect, said that widespread testing is critical for control efforts. “If cheap alternatives like SalivaDirect can be implemented across the country, we may finally get a handle on this pandemic, even before a vaccine,” said Grubaugh.

With the FDA’s emergency use authorization, the testing method is immediately available to other diagnostic laboratories that want to start using the new test, which can be scaled up quickly for use across the nation in the coming weeks (Getty Images)

 

The test is also unique because it does not require a separate nucleic acid extraction step, said scientists. This is significant because the extraction kits used for this step in other tests have been prone to shortages in the past, they explain. Being able to perform a test without these kits enhances the capacity for increased testing while reducing the strain on available resources. Additionally, the SalivaDirect methodology has been validated and authorized for use with different combinations of commonly used reagents and instruments, meaning the test could be used broadly in most high-complexity labs. “A key component of SalivaDirect is that the method has been validated with reagents and instruments from multiple vendors. This flexibility enables continued testing if some vendors encounter supply chain issues, as experienced early in the pandemic,” said experts, adding that this is a huge step forward to make testing more accessible.

Providing this type of flexibility for processing saliva samples to test for Covid-19 infection is "groundbreaking" in terms of efficiency and avoiding shortages of crucial test components like reagents, said Dr Stephen M Hahn, FDA Commissioner.

The Jackson Laboratory for Genomic Medicine in Farmington, Connecticut, will partner with Yale to explore how to implement the test for a broader audience. The research team does not want to commercialize the method. Instead, they want the simplified testing method to help those most in need. Accordingly, Yale plans to provide the SalivaDirect protocol to interested laboratories as an “open source” protocol, implying that designated laboratories could follow the protocol to obtain the required components and perform the test in their lab according to Yale’s instructions for use. Since this test does not rely on any proprietary equipment from Yale and can use a variety of commercially available testing components, it can be assembled and used in high-complexity labs throughout the country, provided they comply with the conditions of authorization in the EUA, says the FDA. 

“This could be one the first major game changers in fighting the pandemic. Rarely am I this enthusiastic...They are turning testing from a bespoke suit to a low cost commodity, tweeted Andy Slavitt, a former acting administrator of the Centers for Medicare and Medicaid Services in the Obama administration.

 



 

 

This is the fifth test that the FDA has authorized that uses saliva as a sample for testing. “Testing saliva eliminates the need for nasopharyngeal swabs, which have also been prone to shortages, and alleviates the patient discomfort associated with these swabs. Since the saliva sample is self-collected under the observation of a healthcare professional, it could also potentially lower the risk posed to healthcare workers responsible for sample collection,” explains the FDA.

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