School health protocol: where is the saliva test campaign?

In recent weeks, the executive has continued to review its copy of health protocol: while a PCR or antigen test was mandatory for students as soon as a case of Covid-19 broke out in a class, followed by a self-test on D + 2 and D + 4, only three self-tests are sufficient, said Jean Castex on France 2 on Monday evening. The Prime Minister also announced the delivery of 11 million new kits in pharmacies during the week, free for children on presentation of a certificate issued by the school.

But beyond the self-tests on which this new protocol relies, what about the screenings organized in schools, and in particular the PCR tests using saliva samples? This technique is only authorized within the framework of such campaigns, or for people for whom the nasopharyngeal swab is difficult or impossible (in the case of displaced nasal partitions for example), specified the High Authority of Health in February 2021.

At school, this campaign was intended to be massive: at the end of May, the Minister of Education Jean-Michel Blanquer promised 600,000 weekly screenings. A figure never before reached. According to the latest update from the ministry, which dates back to December 17, 467,550 saliva tests were offered to students and staff over a week, and only 242,729 of them were carried out.

“The capacities of RT-PCR tests on saliva samples have increased in recent months on the national territory”, however assures the Department of Health contacted by LCI. “The decision to take a saliva or nasopharyngeal sample is up to the medical analysis laboratory, depending on the public, their analytical capacities and demand.”

If the screening campaign is slipping, it is because the PCR test by saliva sample must be analyzed in the laboratory, just like the nasopharyngeal tests, within 24 hours. “If the centers are saturated, the problem is the same as with PCRs that work with a swab”, explains to LCI Thomas Hottier, medical biologist and general manager of the group of laboratories Inovie, which recalls that nine million tests last week, including 30% of PCR. The saliva sample represented 20% of these tests before the holidays, and we almost find this rate today with the return of the children to school after the holidays.

In the school context, there is an additional difficulty: the difficulty in mobilizing staff to support the children in the sample. “It’s easier to do than with a nasopharyngeal test, but you still have to guide them to salivate, tell them to think of something good”, continues the doctor. The administrative procedures to collect the parents’ agreements are also cumbersome.

“At first the teachers and school assistants played along, but now they can’t take it anymore, because they are tired and stressed, which is understandable.”, he emphasizes. Since November, the National Education has instead turned to self-tests, to be carried out outside of school – also cheaper methods, climbing to a few euros against 40 for any PCR test.

However, PCRs using saliva samples are more reliable than self-tests: according to the specialist, their sensitivity rate, that is to say their ability to detect positive cases, climbs to 85-90%. A rate slightly below nasopharyngeal PCR, 100% reliable, but much higher than antigens, 70% reliable for symptomatic people and 50% for asymptomatic. The sensitivity of the self-tests turns around one in two cases.

Saliva sampling also makes it more comfortable for children and easier to collect for parents – except those under 3 years of age, for whom it is difficult to produce enough saliva. “The Association for the Progress of Medical Biology calls for the indications of this test to be broadened, because people can more easily collect the saliva themselves from the young, at a time when there is a shortage of sampling personnel”, points out Thomas Hottier, who affirms that the presence of a pediatrician or any other health personnel is not necessary to accompany the parents.

“There is not overwhelming acceptance of saliva tests at school” from the parents, regretted Jean-Michel Blanquer in an interview with Parisian in November. “Out of 12 million students, 600,000 tests, that’s nothing, and most parents are never seen offered for their children”, objected to LCI the vice-president of the federation of parents of pupils PEEP, Laurent Zameczkowski. The problem remains according to him “the lack of material resources and staff in schools”, considering that the school’s screening policy has generally been “a failure”.

According to him, the parents of students on the contrary favor this solution: nasopharyngeal tests “are not something trivial”, he argues. “For fear of hurting their child, many parents prefer to go to a pharmacy for a health professional to do it”, he explains. “They’re also worried about misusing the swab and getting false negatives.” In addition, taking charge of screening at school would also relieve the parents, he defends: “We have our children tested so that the schools remain open and so that they can continue to work, but it is tedious and the parents tire out.”

According to Thomas Hottier, the solution would be more to combine several methods. “The self-tests are better than nothing, but it would be interesting to end a seven-day cycle with a PCR test with a saliva sample, because that is when the self-test loses sensitivity and a case could go through. under its radars “, he explains. “Let’s use whatever weapons we have, and at the right time.”