Does testing still make sense at 200,000 cases per day?

France turns to more than 200,000 cases of coronavirus per day on average, and is not far from 300,000 cases on Tuesday, according to the Minister of Health Olivier Véran. Record contaminations which generate a test volume which is just as important. The week preceding Christmas, nearly 7.3 million tests – PCR or antigen – were carried out by the French, to which must be added six million self-tests. Never had the positivity rate been so high, showing a particularly active circulation of the virus.

At issue: the Omicron variant, now the majority in France, and which all studies tend to show is much more contagious than the previous strains. So much so that these vertiginous figures could, according to Olivier Véran, still progress. The number of contaminations “will continue to increase in the coming days, predicted the Minister of Health at the microphone of France Inter this Tuesday morning. Omicron’s circulation is very high, and it is all over the planet. We have never recorded so many contaminations around the world. »Therefore, faced with such a surge, is there still any point in testing oneself? In any case, this is the question many professionals are asking themselves.

How to trace such an epidemic?

With such an epidemic outbreak, the strategy of tracing / isolating contact cases indeed seems almost impossible to maintain. At the end of the first wave, the Minister of Health estimated that this policy was relevant below 5,000 cases per day … or 40 times less than currently. “An examination makes sense if it can be done on time and if the response to this examination influences the course of action”, abounds the biologist Jérôme Grosjean. However, obtaining an appointment to be tested is increasingly difficult because of the saturation of laboratories and pharmacies. “Many give up” in front of hours and hours of queue for a test, recognizes the biologist.

He pleads for pragmatism: if you are symptomatic, there is no need to be positive to take precautions, avoid going out, contact: “If you are sick, whatever the virus and the result of a test, you have to protect yourself and others, ”argues the scientist. But the problem with Covid-19, and it won’t have escaped your notice in almost two years of the pandemic (and yes, time flies), is that many people are contagious while being asymptomatic. Hence the contact-tracing policy put in place at the time by the government. But faced with the explosion of cases, how to manage all the contact cases?

Common sense rather than testing

Now, what to do when you are in this situation? In absolute terms, isolating yourself – when possible – obviously seems to be the wisest decision. “But that would be untenable, especially for the normal functioning of society,” admits virologist Yannick Simonin, given the number of jobs that do not allow teleworking. “The period of infection of the Omicron variant nevertheless seems to be reduced”, he adds, synonymous with a potentially shorter isolation. The ideal being to self-isolate and take the test after the five regulatory days of isolation in the absence of symptoms, “even if it means doing a self-test for lack of choice,” says Jérôme Grosjean.

Even the concept of a contact case, at 200,000 cases per day, is getting a bit hazy. Let’s say you are in Paris. At the smallest place containing more than 20 people (the overwhelming majority of bars, restaurants, etc.), you have 66% of being in the company of a positive person, and therefore of being in contact. A percentage that rises to 93% for events of more than 50 people. In this case, in all French departments, the chances of being in the company of at least one positive person are greater than 50%. You can of course avoid this kind of big date. But still in Paris, know that the slightest meeting between two people between 20 and 29 years old has a 17% chance of containing a positive person. With such an epidemic circulation, the population is constantly in contact with the virus.

The question may, in any case, not even arise. In the opinion of December 2 from the High Authority for Health on self-tests, the latter recognizes the inability of the offer of conventional tests (PCR and antigen) to keep up with demand: “The capacity to carry out virological tests carried out by professionals authorized to do so will not be sufficient to cover the entire need for detection in contact persons ”. A mess of tests which also have a huge cost. According to The echoes, the thirty million tests carried out in December, including 28 million reimbursed, will have cost Social Security one billion euros.

The need for vaccination

However, nuance Yannick Simonin, even with so many cases per day, “the tests can help limit the current wave and the associated hospital impact even if it will not stop the epidemic”. Preventive tests can also be reserved for specific events, for example intergenerational meetings or with relatives suffering from co-morbidities. This surge must above all convince of one thing: “It is necessary that all people at risk of resuscitation, roughly the over 40s or / and with comorbidities, get vaccinated to stop making everyone bear this burden of resuscitation. seriously contaminate a few, ”pleads Jérôme Grosjean. Currently, the chances of crossing the virus are immense, you might as well manage not to discover it through intubation.