French scientists may have developed a Covid-19 saliva test which will be ready in weeks

By Ethan Shone
Friday, 18th September 2020, 12:52 pm
Updated Friday, 18th September 2020, 12:53 pm
French lawmakers were told earlier this week that a rapid-results saliva test could be rolled out soon (Photo: Shutterstock)
French lawmakers were told earlier this week that a rapid-results saliva test could be rolled out soon (Photo: Shutterstock)

Rapid result tests for coronavirus should be rolled out across France by the end of this month, according to the president of France’s scientific council.

Professor Jean-Francois Delfraissy told French lawmakers earlier this week that the tests had been successfully trialled in the Paris region and in French Guiana.

Do they work?

The tests have a “sensitivity of 80 per cent” according to Delfraissy, and compared with the current swab method will make it easier and quicker to test the public for Covid-19.

Speaking at a senate hearing, Delfraissy said the saliva tests will produce a result in between 15 minutes and one hour.

The results are available much quicker than with nasal swab tests, as the processes involved are relatively simple. Nasal swab test results require expensive equipment, and hours of laboratory processing time, meaning results usually take days, rather than hours.

Saliva tests only require medical staff able to simply heat the saliva sample in a test tube with special reagents, with the result clear to the naked eye after less than an hour.

What’s the difference?

The current testing method (which involves inserting a cotton swab into the nasal cavity) can be painful for those being tested, as well as carrying the potential for medical personnel to become infected during the testing process.

It is not clear whether the UK government could look to adopt the same testing system, but health experts will likely be looking with keen interest at how these saliva tests perform once they’ve been rolled out.

While the nasal and saliva testing methods differ somewhat in application, they both use the same polymerase chain reaction (PCR) method, which looks to measure the viral load in a patient’s body.

Speaking to TV network FRANCE24, Luke O’Neill, professor of immunology at Trinity College Dublin, described PCR tests as “the gold standard.”

He said, “The dose of the virus in your body determines your level of infectiousness. The lower dose you have, the less likely it is you will infect other people.”