- The latest findings on the coronavirus suggest that the antibodies developed by patients do not necessarily have a lasting and effective protective effect against Covid-19.
- Linking deconfinement to an immunity passport or to group immunity is therefore no longer envisaged by the Scientific Council.
- Researchers around the world are hard at work developing a vaccine against Covid-19.
A pandemic that does not regress. An endless confinement. And the mysteries of a virus that do not unravel. A month after the start of confinement in France, many questions are still unanswered. We just know that the beginning of deconfinement should begin as of May 11, with a gradual reopening of schools and certain businesses, but under conditions that are still unclear. And that will be defined by the executive in the coming weeks. By then, how many of us will be immune to Covid-19? Will we be able to avoid a second wave? when will the vaccine be available?
Collective immunity unlikely to date
A time mentioned as one of the criteria for deconfinement, the immunity passport - consisting in deconfining in priority people who contracted Covid-19 and therefore developed antibodies against the disease, seems today to be ruled out. Prof. Jean-François Delfraissy, immunologist and president of the Scientific Council, has expressed reservations about the capacity of the body of infected people to develop antibodies effectively and durably protecting them from the coronavirus. “This virus is very special. We have noticed that the lifetime of protective antibodies against Covid-19 is very short. And we are seeing more and more cases of recurrences in people who have already had a first infection, "he said in an interview with the Italian daily La Repubblica . Thus, "having antibodies does not totally mean that we are protected," he added on Wednesday during his hearing by the Senate law commission. "This is why our committee no longer recommends an immunity passport, a kind of pass for those who have had a first infection," as a deconfinement criterion, added Professor Delfraissy.
Spread by ricochet, the track of collective immunity, "which can be reached when 60% of the population contracted the virus, indicated Dr. Benjamin Davido, infectiologist at the Raymond-Poincaré hospital in Garches (Hauts-de- Seine) and Covid-19 crisis referral doctor. However, the whole issue of containment measures is precisely to avoid a massive spread of the epidemic ”. Thus, for the time being, “population immunity is around 10%” in the regions most affected by Covid-19, said Professor Delfraissy on Wednesday. For its part, the Scientific Parliamentary Office on the Covid-19 epidemic, after an exchange this Thursday with the National Academy of Medicine, also "noted the still strong uncertainties surrounding the development of collective immunity".
A second wave in the fall?
If the summer, with its high temperatures, "could play a role" in the lull of the virus, the president of the Scientific Council fears that we "end up in September with a bigger epidemic whiff, fears Professor Delfraissy. There are still many unknowns which make that the strategy must be carried out step by step ", he added, calling for" a lot of scientific humility ".
Today, with group immunity estimated at only 10%, the fear of a rebound of the virus is growing. Because it is today "not at the level where we want it to avoid a second wave," said Professor Delfraissy. What could have an influence on the conditions of the deconfinement. Citing the example of Singapore, which is currently experiencing a second very strong epidemic wave, Professor Delfraissy does not exclude that it is necessary “for a long time, free a little, tighten, release [the conditions of the deconfinement] while waiting for we have a certain number of drugs at our disposal ”.
On-the-job research to develop a vaccine
It is therefore on scientific research that hopes are focused. While much of the world is paralyzed by containment, researchers around the world are hard at work developing a vaccine and treatments in record time. Among them, researchers from the Pasteur Institute. "We are trying to understand why some people develop a very good immune response by producing many antibodies capable of effectively neutralizing SARS-CoV-2, and others not. What are the targets of these antibodies on the virus? How do they precisely block the viral cycle? Are they able to destroy infected cells? To answer these questions, we are studying the molecular interactions of antibodies with the virus, but also their antiviral properties, ”explains Hugo Mouquet, head of the laboratory. Because "there are probably protective and neutralizing antibodies and antibodies that can be facilitating" of the virus, abounds Professor Delfraissy. The objective for the Institut Pasteur is therefore to discover and characterize the most neutralizing antibodies, in order to be able to produce them and, possibly, to use them as a vaccine or medicine.
But faced with an emerging virus, it is not an easy thing, and such a discovery is not made with a snap of the fingers. While scientists are hopeful of meeting this crucial challenge, no one knows when they will succeed. But already more than 500 research projects on the Covid-19 are in development around the world. "Making a vaccine is necessarily long," Philippe Gabriel Steg, head of the cardiology department at Bichat hospital in Paris, said on RTL on Thursday. Research has never been carried out as quickly as for the Covid-19, he added. If we have a vaccine in 2021, it will already be a historic record. ”
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