In the coronavirus pandemic that is assaulting the world, collective immunity is struggling to build; a vaccine is therefore essential. A hundred anti-Covid-19 serum projects around the world are underway, including ten in clinical trials, according to recent data from the London School of Hygiene & Tropical Medicine.
If concord and knowledge sharing seem to regulate the race for the vaccine that will immunize us against the coronavirus, each one nevertheless goes with its calendar. The American company Moderna Therapeutics already ensures to test one on a group of 45 healthy patients, Johnson & Johnson plans to do it in September on humans, with a placing on the market "at the beginning of 2021", the German BioNTech has already administered doses to volunteers and with the Pfizer laboratory, extended this Thursday its trial of four different formulas to a panel of Americans. However, if found, it will take months to bring a covid-19 vaccine to market.
Long time is a recent development in the history, however young, of vaccination. "When in 1885 Louis Pasteur tested the rabies vaccine on a young Alsatian seriously bitten by a rabid dog, it took him five months to obtain results with the spinal cord of rabbits," says Maxime Schwartz, molecular biologist, historian Pasteur and vaccines (*). From July to October, it's very fast! In March 1886, 350 people were already vaccinated. Admittedly, Pasteur was already very famous, but that is to tell you if at the time we did not bother with the risks ”. Since then, health authorities have put up safeguards, even more under the weight of opinion which has recently, in part, turned away from vaccines.
“Today, it takes a very large number of people tested to ensure that the risk from the vaccine is extremely low. This requires very long tests, ”he continues. In addition, it is no longer ethically possible to inoculate the virus in men as Pasteur did. "We have to wait until natural exposure does its job".
"Start clinical phases in July"
Different technologies are being developed to find the serum that will immunize us against Covid. "They make it possible to go more or less quickly throughout the design and preclinical part," explains Christophe d'Enfert, scientific director of the Institut Pasteur. “Moderna started its clinical phases in March. For our measles project, we plan to start the clinical phases in July. It's already been four months of difference, ”he says.
The DNA or RNA vaccination technique involves injecting part of the DNA or RNA of the virus into a healthy cell to trigger the production of a protein which in turn will trigger the immune response of our body. This method has been successful in veterinary use, but has so far not shown its effects in humans.
The Pasteur Institute is working on recombinant vaccine technology, that of measles. More tedious, a little slower at the start, but proven. "For chikungunya, we went to phase 3 of clinical trials," says Christophe d'Enfert. The recombinant measles vaccine had worked well for SARS-CoV in 2002-2003, with potential for success "before the virus cleared up on its own, and testing was made impossible. But, with all the data acquired in research against the SARS epidemic, the preclinical phases of a shield against the current coronavirus, could be faster.
"The authorities apply accelerated procedures"
While it is no longer ethically possible to inoculate a virus with lethal potential to test the effectiveness of its immune antidote, the fact that a large part of the planet is naturally exposed to it should also allow the neutralizing effects to be verified more quickly, more quickly in any case than if the covid only made its victims on a continent.
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An effort by the health authorities on the regulations also explains why the deadlines can be shortened. This vaccine, "when we started talking about it at the end of January, it was said that the clinical phases could be completed at the end of the summer of 2021. Today, we are considering the first half of 2021," says the scientific director. In three months, Pasteur researchers have therefore gained three to five. Why ? "Mainly because, from a regulatory point of view, the authorities apply accelerated procedures to handle the files".
There remains the phase of developing a large-scale vaccine. If you can convert a weaving line of tablecloths or t-shirts to produce huge quantities of protective masks, it is more difficult to act this way for vaccines. In 1930, in Lübeck, improper handling of the BCG vaccine led to babies getting TB. Dozens died, while the vaccine alone was effective. This is why the firm Johnson & Johnson is already working to provide more than a billion doses as soon as the effect and the tolerance of its vaccine have been demonstrated. As for the Chinese Sinovac Biotech, he said at the end of April that he had already started production of one hundred million doses per year.
"You may also never find a vaccine against the coronavirus"
However, caution remains in order. Regarding the date of a possible vaccine, Emmanuel Macron warned moreover during one of his recent speeches: "Perhaps at the end of the year, more probably 2021 and perhaps never". Because, yes, you can also never find a vaccine against the coronavirus.
Maxime Schwartz directed the Institut Pasteur between 1988 and 1999, right in the "AIDS years". “It was said that from the moment when animals seem to be walking, it takes ten years. We've been looking since the mid-1980s, we still don't have a vaccine. The main reason is that the virus mutates a lot, even in the same person, and that it attacks the immune system itself. ” Even malaria, despite years of research, still doesn't have its shield. But “someone infected with the coronavirus only presents a variety of the virus, not an entire family. And it doesn't attack the immune system, so there is a very high probability of having a vaccine, ”he concludes.
Beyond the scientific, technological and industrial possibilities, there remains a strong dimension in this race for the first vaccine: political discourse. "In the current situation, medicine and politics are more intensely and visibly linked than ever before," says Dorit Brixius, historian of science and knowledge at the German Historical Institute, based in Paris. "The differences in official rhetoric reveal everything both the quest for power and the helplessness of human beings against nature ”. Faced with the unknown, "there are therefore optimists, realists, pessimists and liars", summarizes the researcher. Who adds a category: "those who want to show themselves in heroic light".
(*) Author, with Annick Perrot, of "Le Neveu de Pasteur ou la Vie aventureuse d'Adrien Loir, scholar and globetrotter (1862-1941)", from Odile Jacob.