SalivaDirect: A Cheaper Technique for COVID-19 Testing
Widespread and rapid testing to detect
coronavirus infections is key during the ongoing pandemic. Catching an
infection early could help contain the spread of the virus and thus help
save lives. Countries around the world have been frustrated over
testing shortages and delays for months now. But a new saliva-based test
for COVID-19 could offer a fast and inexpensive solution to millions of
people.
This laboratory diagnostic test has been
developed by researchers at the Yale School of Public Health and has
been granted authorization from the Food and Drug Administration
recently.
In a recent paper, published on August 4 on the preprint server medRxiv,
a team led by Yale postdoc Chantal Vogels explained the new tool called
'SalivaDirect'. Another team, comprising of many of the same
researchers, had earlier this year detailed that saliva could be
collected in any sterile container and that it remained mostly stable,
without the need for special tubes or preservatives.
“This is a huge step forward to make
testing more accessible,” said Chantal Vogels, a Yale postdoctoral
fellow, who led the laboratory development and validation along with
Doug Brackney, an adjunct assistant clinical professor. “This started
off as an idea in our lab soon after we found saliva to be a promising
sample type of the detection of SARS-CoV-2, and now it has the potential
to be used on a large scale to help protect public health. We are
delighted to make this contribution to the fight against coronavirus.”
How useful is SalivaDirect?
Until now, detecting the novel coronavirus SARS-CoV-2 involved the
reverse transcription-polymerase chain reaction test. This “RT-PCR” test
is conducted by collecting a sample from the back of a person's nose or
mouth. While effective, the nasopharyngeal swabbing is unpleasant and
isn’t cheap either. However, it was chosen as the preferred sampling
technique because of its effectiveness in detecting respiratory
infections over the years.
Unfortunately, there’s a limit to the amount of COVID-19 testing that
can be conducted through this method. This is where the new saliva-based
test could be a game-changer as it promises to be quicker, cheaper,
more flexible, and widely accessible. With saliva being quick and easy
to collect, this test could indeed be a turning point in COVID-19
diagnostics.
So far, the results have shown that SalivaDirect is highly sensitive and
produces similar results as nasopharyngeal swabbing. Now, further tests
are being conducted to see if the method can be successful as a test
for asymptomatic individuals, too. Also, compared to nasopharyngeal
swabs, the authors found a “high agreement” of more than 94 percent in
detecting true positives between the two methods.