Covid-19: infection, vaccine efficacy … what we really know about the ‘Indian’ alternative

Code name: B.1.617. With This is called the “Indian” variant of SARS-CoV-2Government spokesman Gabriel Atal admitted on Wednesday that “a new deal” is underway. More transmissible, causes more serious forms, escape from vaccines … Much has been said about the person described at the start of “double” or “triple mutations”, due to amino acid mutations on the “spike” protein of the virus. This is what allows it to enter our cells.

In this article we evaluate what we know, what looks likely, and what remains for us to speculate. First of all, let’s define that this “Indian” alternative, Classified as “alarming”, Grouping together three different subspecies: B.1.617.1, B.1.617.2, and B.1617.3. This is the second of our priority concern, as it is the majority in France (36 out of 46 outbreaks of at least one Indian-type case were identified on May 25, according to French Public Health). Until now Prevalent among all new types of pollution identified in EnglandThat increased by about 20% in one week.

More contagious, but by how much?

“Transport B.1.617.2 is possibly more transmissible than B.1.1.7 [le variant dit britannique, devenu majoritaire au Royaume-Uni fin décembre puis en France fin février, NDLR] », Public Health England notes at The most recent risk analysisPublished Thursday 27 May. “It has a transmissibility that seems higher than the historical ancestry, but also of variable [« britannique »]We can see it in particular in the laboratory data, “adds Sybil Bernard Stocklin, an epidemiologist at Public Health France.. B.1.1.7 is already more contagious than the starting strain, which caused the first two waves of the epidemic. Scientists generally suggest a range between 40 and 70%.

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The spread of this Indian species is “faster” in the affected areas, including the English cities of Bolton, Bedford and Blackburn, and this “cannot be fully explained by types of contact or behavior.” In other words, population sluggishness cannot on its own explain why B.1.617.2 is spreading there so quickly. The explanation could come from the L452R mutation, “which may be associated with an increased risk of transmissibility of the virus,” she points to Public Health France and the National Reference Center for Viruses of Infectious Diseases. In their latest analysis of the risks.

Video. B.1.617, the “double mutant” variant causing the outbreak in India

How fast does it spread? It is difficult to answer precisely at the moment. The Emergency Scientific Advisory Group (Sage) juge “It could be up to 50% more transmissible.” “Maybe 50% is a little overestimated. Nevertheless, we can clearly see an increase in transmissibility in the cities where this species is more common than others,” confirms epidemiologist Antoine Flahault. Sibylle Bernard-Stoecklin calls on her side to “be cautious” with these numbers, pending “additional data in real life”.

“It is currently spreading faster than B.1.1.7, but we can’t yet know how common it is because it is more contagious or because it evades immunity,” adds biologist Samuel Ellison, director of research at CNRS.

There is no evidence of more severe forms of the disease

“There is no clear evidence yet of a difference in disease severity after infection with this type,” notes the British equivalent of our Scientific Council. “Most of the cases are recent and follow-up time is insufficient to allow an assessment of severity,” adds Public Health England.

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However, hospital admissions increased by 20% in one week, without it being possible to say whether this was a minor consequence of increased infection or if the alternative was also more “bad”. All regions were affected, especially the northwestern region, according to the Financial Times correspondent John Bern Murdoch, who does not hesitate to talk about a new “wave”.

The “positive” point is that the oldest this time appears to be relatively immune to vaccination, which should limit the number of deaths.

The most problematic mutation is missing

What distinguishes B.1.617.2 from the other two subspecies is that it does not contain the E484Q mutation. This is definitely good news. The General Directorate of Health indicated on April 26 that this “may have an effect on immune escape (post-infection and post-vaccination)”.

As is often the case, this has “not been formally proven yet”. Moreover, the variant 201 / E484Q, It also possesses the E484Q mutation and has been detected in several outbreaks in Bordeaux, It appears that the older population has survived and thus vaccinated, the Nouvelle-Aquitaine Regional Health Agency recently reported.

A few cases of reinfection with B.1.617.2 have been identified Across the channel, “But this phenomenon is expected for any prevailing variable,” the French authorities soothe. Preliminary data from England indicate that the efficacy of vaccines will remain roughly as good as B.1.1.7 vaccine, but only with two doses. Of the more than 4,500 people with this type and whose vaccination status is known, nearly three-quarters have not received any dose yet. Nationwide, more than half of the population has received at least one dose.

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“Before the vaccination was published, I thought it would be an illusion to believe that we could differently control the spread of such a variable. I reviewed my judgment, and realized that effectively controlling the transmission chains associated with a new worrisome variable saves time for inoculation,” notes Florence DeBar, CNRS researcher at Evolutionary Biology. Therefore, the “race of the hour” between variables and fortification is more current than ever before.

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