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A vaccine research center in the United States (illustrative image). – AFP
- While on Sunday the WHO recorded a new contamination record in the world, with 660,905 new cases in 24 hours, the vaccine race has begun.
- Sanofi, BioNTech… Several laboratories have started the final stages of their tests, with the aim of major vaccination campaigns starting next year.
- These vaccines, created in a very short time, correspond for some to a new vaccination technique, used until then in cancer research and in animal health. ” 20 minutes “ explains everything.
“If we have more vaccines, we will choose the ones that seem to us the safest and most effective,” Health Minister Olivier Véran said Sunday. Faced with the Covid-19 outbreak, the vaccine rush appears to be a huge hope, as encouraging new studies on the Moderna vaccine were released on Monday.
The opportunity to learn that all vaccines are not made of the same wood and that there are very important differences between the different solutions developed around the world, whether in China, the United States or Europe. 20 minutes provides an update on the five main types of virus vaccines. And among these, those that will be used tomorrow against the pandemic.
The new baby: the messenger RNA vaccine
This is the vaccine developed by Pfizer and BioNTech, 90% effective according to the laboratory, but also by Moderna. It is based on a very innovative technology that has never been used in real life before, except in pig farms, recalls Futura Sciences. It involves injecting the body with strands of genetic instructions called messenger RNA, which tell our cells what to do to fight the coronavirus.
Strength: These vaccines are very quick to create and produce and induce a good response from the immune system. Weak point: They must be stored at a very low temperature, -70 degrees Celsius for Pfizer / BioNTech, which can be an important logistical brake for their worldwide distribution. “RNA must be frozen at very low temperatures for long-term storage. A vaccine that contains a virus or viral proteins can be stored at less severe temperatures, “he explains 20 minutes Judith Mueller, professor at EHESP and researcher at the Institut Pasteur.
Last Thursday Olivier Véran assured that France has equipped itself with 80 super freezers for this purpose. Another obstacle to this vaccine: it requires two doses, just one is not enough to deliver a sufficient immune response. Note that this technique is also developed in cancer research.
Covid-19 peaks with vector vaccines
This is the Oxford / AstraZeneca and Institut Pasteur method. It is similar to that of the vaccine used against Ebola. In principle: part of the genetic sequences of the coronavirus spike protein (the characteristic spikes of the virus) will be associated with another virus, such as adenovirus (chimpanzee cold virus for example, very well known and harmless to humans) in order to trigger a stronger immune response. “These spikes are found on the surface of the virus and are easily accessible to the immune system. They play a very specific role in the virulence of the virus, that is, in its ability to cause disease. Most vaccines under development target these plugs to have a good protective effect, ”says Judith Mueller.
Influenza, poliomyelitis and … Covid-19: inactivated vaccines
“We take the virus itself and make a preparation, which we inactivate by chemical means, heat or physical processes, such as UV exposure for example,” explains Prof. Olivier Schwartz, head of the Virus unit. and immunity at the Institut Pasteur. Even “killed”, the virus retains its structure and is recognized by the immune system. It is on this model that the Chinese Sinopharm laboratory is based to develop its vaccine, in phase 3 of development.
Yellow fever and measles… Attenuated vaccines
With this type of vaccine, “we take the virus itself, but we modify it to maintain its ability to multiply, but at a very low noise,” says Professor Schwartz. The virus, which is not pathogenic, multiplies in the body, which is then exposed to the virus over a period of time. “It induces a good immune system response,” he confirms.
Hepatitis B, papillomavirus and Covid-19 … The subunit vaccine
To make this vaccine, you take a synthetically produced protein and inject it. “Immunity is not the best, so we add adjuvants to increase it. It activates the immune system and induces a better response, “explains Professor Schwartz. This is one of the methods chosen by the French Sanofi laboratory.
As to which of these vaccines will be the most effective against coronavirus, it is impossible today. “The current results are very encouraging but are still preliminary. Vaccinology is an experimental science, you have to test to find out which strategy will work, ”concludes Professor Schwartz.
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