'Fast, cheap, painless': Covid saliva test from French lab
Researchers say a Covid-19 saliva test trialled in France is quicker, cheaper and less painful than other tests, and especially effective at identifying asymptomatic Covid-19 carriers.
Researchers at the CHU hospital in Montpellier revealed a new Covid-19 saliva test, called EasyCov, yesterday (October 5).
Dr Franck Molina, director of research at CNRS, told news source the HuffPost: “We made the test to be low-tech, affordable, waste-free and easy to use.”
The new tests also take only 40 minutes to give a colour-coded result, and are less invasive than existing methods, including blood tests, PCR tests and rapid antigen tests.
Trials for the test were lead by researchers from from CHU Montpellier, national scientific research centre, CNRS and technology company Alcen.
Saliva tests faster, cheaper and less painful
Researchers say the EasyCov saliva tests have some significant advantages over other Covid-19 testing methods. Firstly, they are faster and less invasive.
Researcher Professor Jacques Reynes told news source HuffPost the initial EasyCov saliva sample is taken from under the tongue by micropipette. He said: “It is particularly easy to do and less uncomfortable than testing by taking nasal swabs.”
Results are then available within 40 minutes.
Professor Reynes explained: “We take saliva from the mouth cavity. Then we put the sample in a first tube that we heat to 80C, then a second heated for 30 minutes at 65C. We have a colour-coded result in 40 minutes. Bright yellow is positive, and orange is negative.”
Researchers have priced the saliva test at around €20, with testing centres also needing to buy heating apparatus at a cost of €1,500. This makes individual tests cheaper than PCR tests, which cost €54. In addition, the EasyCov saliva tests use less material than PCR testing, reducing the risk of contamination for medical professionals.
New method improves reliability
On September 18 the health authority Haute autorité de santé raised concerns that existing saliva tests (which use polymerase chain reaction techniques, the same as those used in nasal PCR tests) were only effective in asymptomatic patients.
Researchers in Montpellier have found that introducing a new saliva testing method (Reverse Transcription Loop-mediated Isothermal Amplification, known as RT-LAMP) has improved results.
EasyCov trials in September tested 220 patients, 40 of which were known to be infected with Covid-19. All patients were given PCR and EasyCov saliva tests, with the saliva tests detecting the sick patients with an 87.5% success rate.
The saliva tests were also found to have a very low false positive rate, at 0.6%.
Saliva tests 'will replace' PCR by 2021
Dr Molina told HuffPost that the saliva tests are “particularly effective, as they detect people who are asymptomatic with precision. The tests found 8 out of 8 people who turned out to be asymptomatic".
He added: “As it is those people who are the most infectious we need to test all asymptomatic people if we want to emerge from the health crisis. That’s why saliva tests are a solution.”
Dr Molina said the tests could be particularly useful in elderly care homes, for dentists and in classrooms. He explained: “If there is suspicion of one case in a classroom, we can test the whole class within 40 minutes before the students have even sat down. Then we can test them the next day, and the day after to make sure no one is sick.”
The EasyCov saliva tests studies have not yet been peer-reviewed or published in a scientific journal.
Yet Dr Molina believes the initial results should suffice for approval from the Haute autorité de santé. The doctor predicts that “between now and 2021, PCR tests will completely disappear. They will be replaced by our new testing technique”.
Latest Covid figures in France
The latest Covid-19 figures from health body Santé publique France were released yesterday (October 5). They show there were 5,084 new Covid cases reported in the 24 hours prior, and there are 1,340 clusters currently being investigated.
Hospitals in France have received 4,355 new Covid patients in the past seven days, with 908 in intensive care.
There were over 70 Covid-related deaths in the past 24 hours.
The rate of positivity in France has risen to 8.6%.