Rise in Covid cases, increase in hospitalizations, closure of classes or even schools, businesses and administrations again disrupted… In the United States, the last few weeks have been marked by a clear resumption of the circulation of the virus, with its share of serious forms. A rebound largely linked to the return of children to school: “It is clearly the amplifying element. Contaminated pupils infect their comrades, and these in turn bring the virus back to their families”, indicates Professor Bruno Lina, member of the Health Risk Watch and Anticipation Committee (Covars). While the Covid-19 has already been circulating a little more markedly in France since the middle of August, should we expect to find ourselves quickly in the same situation, with the start of the school year taking place on Monday September 4?
For the moment, it is the same version of Sars-CoV-2 which walks its spicules on both sides of the Atlantic: EG.5, nicknamed “Eris” by some. And, of course, the end of the holidays and the return of students to school and employees in companies, as well as the increase in the use of public transport remain favorable periods for respiratory viruses, Covid in the lead. “In recent years, the months of October to December have always been marked by episodes of epidemic circulation. So such an emergence is part of the realm of the possible”, continues Professor Lina. However, the American context differs in several points from ours, and the experts want to be rather reassuring at this stage.
“In the United States, the population is less well vaccinated than in Europe, especially in the Republican Trumpist counties, which are often very antivax and antiscience. They therefore continue to pay a heavier price than us at Covid”, recalls epidemiologist Antoine Flahault, director of the Institute of Global Health at the University of Geneva, Switzerland. On the Old Continent, people suffering from hypertension, diabetes or obesity, very exposed to serious forms during the first waves, are now well protected. This is not yet the case across the Atlantic, where these pathologies also affect a much larger proportion of the population. Last difference, less access to care: “Due to the lack of universal social security coverage, part of the population may also encounter difficulties in obtaining Paxlovid, a drug whose effectiveness in preventing serious forms in the event of of infection has yet been demonstrated”, adds Professor Flahault. In France, on the contrary, this treatment is widely available.
If necessary, the vaccination campaign could be brought forward
However, as we know, the protection conferred by previous infections and by vaccination weakens over time, due to a regular decrease in the quantity of neutralizing antibodies. This has no particular consequences for the general population: thanks to the persistence of another part of our immunity, cellular immunity, healthy adults are little exposed to serious forms. The same is not true for the most fragile, elderly people with risk factors, or for pregnant women, if they are more than six months away from their last immunization, whether by vaccination or by an infection. In this case, they are again exposed to more severe forms, which can lead to hospitalization.
This is why the health authorities say they are ready, if necessary, to bring forward the start of the recall campaign, currently scheduled for October 17, as the president of Covars recently indicated to L’Express, Brigitte Autran: “The new vaccines adapted to the variants in circulation have been ordered. They are being manufactured and should be delivered in September in France.” For its part, Pfizer has confirmed that it is ready to distribute the doses to the States as soon as the European Medicines Agency has given its marketing authorization – which has just been done.
“For the moment, we have few signs raising fears of new strong epidemic waves, with saturation of hospitals, summarizes epidemiologist Antoine Flahault. This does not mean that we should not seek to protect people at risk. , by improving the air quality in closed places, nor that there will be no long Covid, because it is known that approximately 10% of people infected with variants of the Omicron family will develop persistent forms and disabling.” So many reasons to continue to adopt precautionary measures, pleads Professor Bruno Lina: “By testing your children if they show symptoms, by keeping them at home if they are positive, we help to break chains of transmission. It won’t stop an epidemic from starting, but it will help prevent it from growing too quickly.”
BA.2.86, closely watched
Specialists nevertheless continue to monitor like milk on the fire the latest addition to the Omicron family, named “BA.2.86”, which has just made its appearance in France. This newcomer, with 100 mutations on the counter, including 30 on its Spike protein (the protein that forms the spicules on its surface, thanks to which it binds to our cells), emerged a fortnight ago in several countries simultaneously. “It is likely that it appeared in an immunocompromised person, then circulated quietly,” assumes Professor Lina. By August 31, 26 viruses had been sequenced in Europe, the United States and Africa. In view of the mutations identified, scientists believe that it would largely escape our immunity. “But will it have a sufficient advantage to supplant the currently dominant viruses? It is difficult to answer this question, in the absence for the moment of more in-depth analyzes”, indicates the specialist.
In the worst case, it could both present strong evasion abilities to our immune system and prove to be very transmissible. It would then come to put our health systems under pressure again, infecting a large number of fragile people. Without, however, here again, causing waves of the magnitude of those recorded in the past: “We remain in the Omicron family, with a virus whose potential for gravity remains very low”, assures Bruno Lina. The new Minister of Health, Aurélien Rousseau, therefore considers that BA.2.86 “does not call for any particular response for the moment”. In the United Kingdom, the health authorities have a different analysis: the British Minister of Health has just asked the NHS, which manages the health system, to bring forward the vaccination campaign because of the emergence of this varying.