FOCUS – Several mutant strains of Covid-19 detected in France in recent months have captured the attention of scientists and the media, before being finally brought under control.
They sometimes do pschitt. Several variants of Covid-19 detected in France, such as that of Bordeaux (20I / 484Q), were a source of concern. However, in recent months, no supposedly more dangerous strain detected in France has succeeded – for the time being – to dethrone the English variant and to a lesser extent the South African and the Brazilian. “Not all sparks lead to fire, concedes Pascal Crepey, epidemiologist at the Rennes School of Public Health Studies. “The variants detected are not necessarily more problematic, and then there is a random aspect, a human factor. There is always a chance of extinction at startupHe continues. Overview of the variants that have worried us in recent months.
January 2021. Stupor in the Grand Est. The “California variant” of Covid is detected in an Alsatian hospital, then, a few weeks later, a cluster is identified in the town of Saverne (Bas-Rhin). At that time, this B1.1.429 strain was gaining ground in Southern California, where it accounts for roughly half of the cases. She is accused of igniting the epidemic in Los Angeles. This variant is then suspected of being resistant to vaccines, and of being more transmissible.
But, according to Public Health France, we subsequently identified only “sporadic cases»In France and the West Indies. In flash surveys, which “map” the situation at regular intervals, it has not appeared since March 30. The news is also reassuring in the United States, where cases are on the decline. “There is no reason to believe that our vaccines do not provide effective protectionAgainst this Californian variant, said Dr. Eric Topol, professor of molecular medicine, at Los Angeles Times.
He was the mutant of all fears. In mid-March 2021, eight cases of a variant of Covid-19, B.1.616, were discovered in a cluster within the Lannion hospital (Côtes-d’Armor). All the French and international media flocked to this usually peaceful city, because this “Breton variant»Displayed an atypical profile. The Institut Pasteur reported “nine mutations“And warned of a risk of”underdiagnosis»: It seemed undetectable by PCR tests and required a deeper sample in the respiratory tract.
Today he would be under control. As of April 28, 2021, 40 infections with this B.1.616 strain have been identified. Three weeks later, on May 18, there were only 4 more. Almost all the cases are linked, directly or indirectly, with the original Breton cluster. Scientists feared it would circulate in silence, but this scenario seems to be receding: “If the variant had continued to develop, chains of transmission would now have been created, we would have had people hospitalized, showing symptoms of Covid but with a negative PCR test. Obviously this is not the case“, Estimates Pascal Crepey.
On March 28, the local Alsatian press alerted on an indigenous variant detected at the Strasbourg University Hospital. Like the Breton variant, the screening tests remain negative, despite certain contamination. However, nothing new under the sun, will rectify the next day Professor Samira Fafi-Kremer, from the virology laboratory of the hospitals of the Alsatian capital, contacted by the newspaper. 20 minutes: “It was found that the variant was already circulating almost everywhere in the world, especially in Europe ”. It would be less virulent than the other variants.
The “Henri Mondor” variant, named after the Créteil hospital where it was detected, aroused concerns for a time because of the large number of mutations it presented (18), and an increased risk of transmissibility. On March 2, it represented 1.8% of cases in France. According to Public Health France, it is “today in decline ”. Less than ten cases per week have been detected since mid-April and it has not appeared in the last two “flash surveys“. It is even in the process of disappearing in Germany.
From the start, it was a misunderstanding. The “Belgian variantWas actually from the Democratic Republic of the Congo. In addition to the flat country, where it was sequenced, the B 1.214 was also circulating in seventeen countries, including France, at the end of March. He was worried because he presented an unprecedented function of mutations: an insertion of nine nucleotides in the sequence of the Spike protein. “Never seen before», Affirmed to the newspaper The evening, Vincent Bours, head of the Liège virus analysis and sequencing laboratory.
According to the flash surveys of Public Health France, it also seems to be losing ground. At the end of March, it represented 1.2% of contaminations in France. But his mad rush was stopped. It seems responsible today for 0.2% of Covid cases. It is detected “sporadically“, But seems to have”no impact on public health demonstrated to date“.