Covid-19: why have the French been tested less?

A decline continues for three weeks, then a slight jump. According to the latest report from Public Health France, published on May 6, the screening rate (PCR and antigen tests) increased by 7% between April 26 and May 2, after three consecutive weeks of decline, including a drop of 23 % observed around mid-April. A decrease “More marked among 0-14 year olds (- 45%)” then noted the health agency, who saw a probable link “With the end of screening campaigns in schools in the context of the closure of establishments. “

What about today ? If the French seem to have found their way back to laboratories and pharmacies in recent days, they tend to slow down, observes Michèle Legeas. “For me, the reason is quite simple and is that a lot of grandparents are vaccinated. However, many tests were first carried out so as not to risk contaminating them ”, estimates this teacher at the School of Higher Studies in Public Health (EHESP).

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The lesser use of screening could also be a sign of a more reasoned use of tests, according to her. “Not so long ago, many people were tested before going to see such and such a person, even though they had remained in their bubble for weeks, without the risk of meeting people with carriers. Of course, testing is necessary to block the circulation of the virus, but it only makes sense if one has been exposed. This is perhaps what is better understood today ”, analyzes the health risk specialist.

Caution in interpretation

So much for the probable causes of the slowdown. It remains to wonder about its consequences. Can this lesser screening partly explain, and therefore call into question, the drop in incidence rates that the authorities are welcoming at the time of deconfinement? This is what Public Health France seems to suggest.. “The sharp decrease in the screening rate encourages us to remain cautious in interpreting the dynamics of population incidence indicators”, we read in his point of April 22.

“The screening rate is an indicator to follow closely but it is not in itself decisive, especially since it is not a massive dropout”, nuance Michèle Legeas, who reminds that the tools for measuring the epidemic are constantly evolving. “It hasn’t stopped changing. At the beginning, there were no tests, then they were available on prescription, then open to everyone, then there was the antigenic tests… ”, she enumerates.

“An administrative formality more than a medical act”

For this academic, it is above all the positivity rate that must be looked at, that is to say the number of positive cases among the tests carried out. However, this rate, which has been rather stable in recent weeks, has indeed slowed down – 7.4% between April 26 and May 2, against 9.9% the two previous weeks. An equally significant shift in the 700 and some laboratories of the Biogroup network, indicates its spokesperson, Laurent Kbaier. ” In week 17 (from April 26 to May 2, Editor’s note), we went from 11.6% of positive tests to 8.8% in all of our laboratories ”, emphasizes the doctor.

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As for the drop in screenings, it should only be temporary according to him. “It was the same thing last year at the same time, he recounts. It is the month of May, the weather is starting to be nice, people want to think of something else… But from June, we will collapse under requests for PCR from people who want to go on vacation ”, predicts the biologist, who regrets that screening has become a bit “An administrative formality”. “We have more the impression of being there to put on a tampon than for a medical procedure …”


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