Spit test from Yale awaits FDA OK

NEW HAVEN — A test for the coronavirus that uses saliva rather than a long swab up the nostrils may soon may be available for widespread use.

Developed by Chantal Vogels, a post-doctoral fellow, and others in assistant professor Nathan Grubaugh’s lab at the Yale School of Public Health, the test, SalivaDirect, is expected to receive approval by the Food and Drug Administration by the end of the week, Vogels, the lead investigator, said Tuesday.

The goal was to make testing for the virus that causes COVID-19 “simpler, less expensive, faster, making it more available for large-scale testing and screening,” Vogels said. Results of the test are available in less than three hours, she said.

As colleges, businesses and other institutions begin to open and require frequent testing for the virus, sampling saliva would be preferable to using a long swab that is inserted through the nostrils to the back of the throat. It’s safer too, because the nasopharyngeal swab can cause someone to cough or sneeze.

“If you essentially spit into a tube, that is less risk for the people who are taking the sample,” Vogels said.

The School of Public Health has used samples from patients and health care workers to develop the test, starting in early March, “when things were really getting crazy,” she said.

The researchers also hope to use the saliva test on people who don’t have symptoms of COVID, which current tests are not as capable in detecting. The School of Public Health has partnered with the National Basketball Association and its players union to study how the two types of tests compare.

“A couple of months back they reached out to us, to Nate,” Vogels said. “Essentially they wanted help to get testing more available. … These are all healthy individuals. It’s kind of a unique way to get these samples and get the data that we need.”

Testing asymptomatic people will be part of a follow-up application to the FDA, but the test will be the same, she said. It’s been designed so that each sample needs to be tested just once, rather than three times in the standard test.

In comparing the swab and saliva tests, “we found that the results are really similar,” with positive agreement of 94 percent, Vogels said. The saliva test even picked up some false negatives from the swab tests, she said.

The saliva is tested by combining it with an enzyme, proteinase K, and heating it, then tested with a polymerase chain reaction. “The most unique aspect of SalivaDirect is we have validated different enzymes and different agents,” Vogels said. “We picked products that are already available and we tested multiple ones so that if any of the vendors have a supply chain problem you can use another one.”

The lab’s FDA application for an emergency use authorization was written so that other labs will be able to use the test without having to go through the same regulatory hurdles.

“Once our application is approved, they can just start to use it,” Vogels said. “We already … get a lot of emails from labs and even companies that want to use it. I think it’s going to be used a lot all over the country and in other countries as well.”

The next steps in the research will be to develop a way to pool samples so that many tests can be conducted simultaneously. If a pool comes back negative, no further testing is needed. If there is a positive result, then the remainder of the samples can be tested individually to determine who has been exposed to the virus.

They also hope to develop robots “to analyze thousands and thousands of samples a day,” Vogels said. The goal is to make the test available in remote areas at low cost.

Vogels is an epidemiologist who normally works with viruses associated with mosquitoes and ticks. But a saliva test for the coronavirus could have a big impact on controlling the spread of COVID-19.

“It feels good to be doing something like this,” she said.

edward.stannard @hearstmediact.com; 203-680-9382