Like every new episode of this long Covid-19 epidemic, the media coverage of two “French” variants in March raised fears of the worst.
The "19B / 501Y" and the "20C / H655Y", the scientific names of the two newcomers, better known as the "Henri-Mondor variant" and "Breton variant" are still classified as "to be followed" by the health authorities, but do not know of an explosion for the moment.
These variants are studied by the researchers and scrutinized during each "Flash" survey, carried out every two weeks.
During the last wave, the “Henri-Mondor” variant, so named because of its discovery at the University Hospital of Créteil, only displayed 0.2% prevalence at the national level, against 1.8% on the study. previous.
"A little stifled by the English variant"
"The Henri-Mondor variant was mainly present in the east of Paris, in the Dordogne and a little in Brittany," explains the virologist and head of the biology department of the Créteil hospital Jean-Michel Pawlotsky.
There was a good job of tracing and isolation on the part of the ARS
(Editor's note: regional health agency)
which caused this decrease, but it has not disappeared.
It suffices for it to accidentally infect a cluster and find favorable propagation conditions to gain momentum, which is what justifies monitoring it.
He is, for the moment, a little stifled by the English variant.
"
Researchers are trying to refine their knowledge about it.
“The Henri-Mondor variant is a priori neither more nor less dangerous than the others, states Professor Pawlotsky.
Like the South African and Brazilian variants, it has characteristics that may decrease its sensitivity to neutralizing antibodies.
We will soon have more precise results on this subject thanks to work on cell cultures.
"
The Breton variant, detected in Lannion (Côtes-d'Armor), only has twenty-six confirmed cases for twelve deaths, but remains monitored.
All the proven cases have been in Brittany or in people "having contact with the zone of circulation of the virus", announces Public Health France in its latest situation bulletin.
The death rate among the cases detected is obviously a concern, but it should be put into perspective.
"We only see the tip of the iceberg"
“There is a big calculation bias, because it is difficult to detect at the nasopharyngeal level, points out Vincent Thibault, head of the virology department of the Rennes University Hospital (Ille-et-Vilaine).
It is found on deep lung samples in severe cases.
We must be vigilant because we only see the tip of the iceberg, there are many cases that escape us.
"
Among the twenty-two cases documented in the last investigation of Public Health France, only six had been the subject of a positive PCR test.
“This can mean that we took too late or that this variant goes directly into the lower respiratory tract,” says Astrid Vabret, head of the virology department at the CHU de Caen (Calvados).
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Knowledge of the specific characteristics of this strain discovered at Lannion remains partial, as Pr Thibault cautiously explains: “Certain mutations could give rise to fear of an escape from vaccination, but there are no confirmed data.
We do not have the impression that this strain has a very efficient diffusion, because if it is not found at the oropharyngeal level, it means that the transmission must be low.
The results of the sixth Flash survey, expected in the coming days, will offer a new idea of the position of the different variants, French and international, in the shadow of the English variant.
