Since the beginning of the year, with each appearance of a variant considered “worrying”, health actors, political leaders and the entire population are asking the same question: are the vaccines developed able to counter the effects of this new coronavirus mutation ? Last weekend, asked about AstraZeneca’s product, Emmanuel Macron considered besides that “this vaccine […] will help us out of the crisis. But to respond to variants, since we are talking about future orders, we see that other vaccines are more effective today. A race against the world time has indeed started between the speed of mutation of the virus and the development of ever more comprehensive vaccines.
This week’s publication in the renowned scientific journal Nature, of work carried out by researchers at Duke University in North Carolina, seems to be a boost in the search for a cure ready for any adaptation. According to these scientists, a new vaccine, called “pan coronavirus”, could be very effective against “Covid-19, its variants and other coronaviruses […] and the next epidemics ”. They would have found the “Achilles heel” of SARS-CoV 2.
This potential vaccine developed by members of the Duke Human Vaccine Institute, including immunologists, “triggers neutralizing antibodies via a nanoparticle,” according to a press release from the University. In this preclinical work, they were able to test their products on mice and a handful of monkeys. “In tests of its effect on monkeys, the nanoparticle vaccine blocked the Covid-19 infection 100%. The new vaccine also caused significantly higher levels of neutralization in animals than current vaccine solutions or natural infection in humans, “they argue, as well as” on variants of concern originating in the United Kingdom of South Africa and Brazil ”.
Prevent the virus from entering cells
To understand the scientific process of this “nanoparticle” vaccine, Yves Gaudin, virologist at the Institute for Integrative Cell Biology at Paris-Saclay and Director of Research at CNRS, read this work from the United States. “They use an original and interesting strategy. The technology is quite simple: they inject into the body a nanoparticle – of the order of 25 nanometers (1 nanometer equals one billionth of a meter) – which will produce antibodies that will bind to the Spike protein. She is the one who allows the virus to attach itself to cells (pulmonary in particular) ”, he summarizes. The virus could therefore no longer infect them.
“The use of this nanoparticle, ferritin (a protein of bacterial origin allowing the storage of iron), associated with the Spike protein led to the production of antibodies in the macaques in which they were able to inoculate it. , observes Marlène Dreux, researcher at Inserm in immuno-virology and research team leader at CIRI, ENS de Lyon. Obviously, the antibodies produced by this immunization block infection by various variants of Covid ”.
“The immune response induced by this vaccination in monkeys seems robust enough to protect against infection by SARS-CoV2 and prevent the virus from replicating”, observes Marlène Dreux. And his colleague adds: ferritin particles, made up of 24 identical molecules, each associated with a domain of the spike, effectively stimulate the immune system. This study even says that these results are better than messenger RNA technology (used in the Pfizer and Moderna vaccines) by producing even more antibodies. The difference with these vaccines, already used, is that we inject the protein directly instead of having it produced by our body. But these are only the first preclinical trials at this stage, ”says Yves Gaudin.
A process which is “quite similar to that of the Novavax vaccine », Whose first marketing request has just been postponed to the third quarter. “Basically what we did was take multiple copies of a small part of the coronavirus so that our immune system responds to it more,” says one of the authors. […] We believe this is why this vaccine is effective against SARS-CoV-1, SARS-CoV-2 and at least four of its current variants, as well as other animal coronaviruses ”.
Work still to be confirmed on a large scale and on humans
However, if French researchers are enthusiastic about the potential, they point to a need for more extensive and in-depth validation. “We will have to see if this vaccine formulation strategy can go to the end. First, clinical trials will be necessary. If they are conclusive, the process will have to be further industrialized, ”warns Yves Gaudin. If she judges the analyzes “of a very good level”, the Inserm researcher raises a number of questions.
“In this publication, they present the protections against infections carried out a few weeks (maximum 9 weeks) after the end of the vaccination in monkeys. We will have to see how this protection lasts over time. The sample should also be enlarged beyond five macaques and carry out a comparison study with existing vaccines. Before moving on to humans, for whom the results can also be different, ”she raises.
In the United States, the authors say they see in the long term. “There have been three coronavirus outbreaks in the past twenty years, so there is a need to develop effective vaccines that can target these pathogens before the next pandemic,” it says. “This work represents a vaccine that could prevent, quickly temper or extinguish a pandemic ».