The test is considered slightly less accurate than the nasal swab, but it is easier and more pleasant to use, and is being rolled out in schools, followed by universities, to ramp up mass testing in educational settings.

It will not be used on contact cases or people with symptoms.

The test involves spitting a small amount of saliva into a tube, which is then analysed in a laboratory.

Unlike the nasal-swab antigen tests, the saliva test does not give on-the-spot results but has to be sent to a laboratory to be analysed.

Mass testing of  pupils and staff has been promoted by the French government as a way of keeping schools open but the virus under control, but many pupils found the nasal swab tests uncomfortable or distressing, so the new saliva test is being rolled out first in schools.

It will then be extended to universities, which are currently running around half of classes with in-person teaching.

“We are going to multiply collective screening operations, notably in schools (…), but also in universities,” Health Minister Olivier Véran announced, adding that the saliva test was “more comfortable” for children.

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The saliva test was last week given the green light for use from France's medical regulator Haut Autorité de Santé, which recommended it for use in asymptomatic people.

Epidemiologist Catherine Hill of the Gustave Roussy institute told France Info: “The salivary test is a little less effective but it is so much more practical and we can have such a better coverage rate that it is absolutely worth it.