Harvard researchers in a study point to the lack of precision of PCR tests, which do not allow the viral load of a patient positive for the coronavirus to be evaluated, and therefore to establish whether or not it represents a danger for his next.

But for the French researcher Anne Goffard, the precautionary principle must be privileged.

Nearly 9,000 new cases of Covid-19 have been detected in the past 24 hours in France, according to figures announced Friday by the Directorate General of Health.

This is a new record since deconfinement, which must however be compared with the increase in the number of tests carried out across the country: more than a million carried out in one week.

American experts at Harvard, however, questioned in a study taken up by

New York Time

s on the relevance of massive screening policies which do not make it possible to establish whether a positive person is necessarily contagious, and thus lead to accusations. unnecessary quarantine.

In fact, these doctors wonder about the finesse of PCR tests.

They only let you know whether or not the virus is present in the patient's body, but the results do not give the viral load, that is, the amount of virus present in the body.

The higher it is, the more contagious the patient.

According to American experts, a majority of patients who test positive in fact carry only a fairly insignificant amount of the virus and therefore end up in isolation, despite the fact that they are probably not or not very contagious.

>> LIVE -

Coronavirus: follow the evolution of the situation Saturday, September 5

"I prefer that we overestimate the number of positive people"

But for Anne Goffard, researcher at the Lille Infection and Immunity Center, zero risk does not exist.

“Just because a person has a low viral load doesn't mean that they don't get infected at all,” she explains.

"I prefer that we overestimate the number of positive people and ask people to take precautions, by wearing the mask or staying away for seven days, rather than allowing them to walk around unprotected. contaminated people that we would not have detected well. "

For this specialist, PCR tests must be continued in order to be able to detect as many cases as possible, especially in asymptomatic people.

But to cope with the increase in demand and the queues that are lengthening in front of screening centers, she believes that a priority route should be created to first test contact cases and people at risk.