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The World Health Organization warned about a new variant of Covid-19 called Mu, identified for the first time in Colombia and that could be more resistant to antibodies due to its mutations. France 24 reports on the so-called “immune escape” that threatens the effectiveness of coronavirus vaccines.
While the public authorities intensify their vaccination campaigns around the world to put an end to the Covid-19 pandemic, the appearance of mutations of the virus considered more resistant to the vaccine continues to worry.
While the Delta variant, identified in India, today it is predominant in France and in the world, the World Health Organization recently identified several new mutations baptized Mu, Lambda or Epsilon, which would also present a risk called “immune escape”, neutralizing to a certain extent the antibodies present as a result of vaccination or a previous infection.
To better understand this notion that has become crucial in the fight against Covid-19, France 24 interviewed Professor Jean-Daniel Lelièvre, head of the immunology and infectious diseases service at the Henri-Mondor hospital in Créteil.
France 24: Could you explain to what corresponds the risk of immune escape mentioned by the WHO regarding the new variants?
Jean-Daniel Lelièvre: Immunological escape refers to a lower effectiveness of protection in vaccinated people or in those who have already been ill against certain viral strains responsible for Covid-19. Such people have developed antibodies that give them immunity for several months, which will wane over time. But Covid-19 has the peculiarity of mutating fast and a lot.
The more the new version of the virus is different from the original, the more the pre-existing immunity is weakened. However, although the vast majority of the variants do not pose particular problems, in some of them modifications are observed that are somewhat flaws and can make the antibodies less effective.
Does this immune escape currently threaten the efficacy of vaccine protection?
Today there are two major problems with variants: immune escape, which makes immunized people more vulnerable; and a higher level of contagion observed in some variants, such as the Alpha and Beta variants. With the spread of Covid-19 throughout the world, the variants that become predominant tend to group these two characteristics. Currently, people vaccinated with the initial form continue to be protected from the severe forms of Covid-19, even against the new variants. But the question is to know for how long …
So far, we have not detected mutations that are sufficiently distinct from the strain to significantly reduce the efficacy of the vaccine, because the antibodies are not unique and attack several important parts of the virus. But we cannot completely exclude this risk, because it is necessary to recognize that we were surprised by the rapidity of the appearance of Sars-CoV-2 variants, and we still do not fully understand the mechanisms of selection for virus mutations.
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What sanitary measures make it possible to combat this risk of immune escape as well as possible?
The risk of immune escape is one of the reasons to expand vaccination as much as possible: the more the spread of Covid-19 among the population is prevented, the more its mutational capacities are reduced. In fact, it is after periods of lifting of restrictions that important mutations of Covid-19 have been observed, and in particular the appearance of the Delta variant.
So it is necessary to block the transmission chains with the barrier gestures, of course, but also – and above all – mass vaccination. The difficulty today is that we are immersed in a race against time, but we lack data.
With sequencing we detect these modifications, sometimes in critical parts for the immune response, but then it is necessary to analyze the evolution of the variant because only if it predominates over the other variants should particular attention be paid to it.
So it is necessary to adapt the vaccination policy according to the evolution of the risk. Given these new variants that present worrisome mutations, it seems necessary today to move towards the generalization of the third dose for the whole population to maintain a sufficient level of vaccination efficacy.
This article was adapted from his original in French
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