Pfizer, Moderna, Sanofi, Sputnik vaccines: Beyond the announcement effects, what should we remember?

In recent days, press releases have been pouring in from companies in the race to develop vaccines against Covid-19. It was first of all the Pfizer and BioNTech alliance which announced that it had developed a 90% effective vaccine. Then, Moderna communicated that his vaccine is even more efficient with 94,5%. The vaccine developed by Russia: Sputnik V is not left out, with a rate of 92% protection. BioNTech / Pfizer has since announced the final results of their Phase 3 study, with results leading to 95% the effectiveness of their vaccine.

THEFrench company Sanofi-Pasteur, meanwhile, is a little behind its competitors, still in the preclinical testing stage, but seems confident enough to launch a massive production.

To take stock, we interview Marie-Paule Kieny, vaccinologist. Research Director at Inserm, she is president of the Covid-19 Vaccine Committee set up by the Ministries of Research and Health to assess vaccine candidates.

The Conversation: Different companies report efficiency rates of around 90% or even 95%, were you surprised?

Marie-Paule Kieny: These efficacy rates were a great surprise for everyone, our community did not imagine this order of magnitude from the first vaccines. This is very good news. This allows us to look to the future with optimism, but we still ignore some very important parameters.

First of all, long-term effectiveness. Ideally, a vaccine should protect against a disease for a long time, and if possible for life, like the vaccine against yellow fever. At this point, we cannot predict the rate of protection after 3, 6, 12 months or more. The number is expected to drop, the question being by what factor.

The second, very important question: will the elderly be well protected? In fact, serious forms and deaths are mainly counted in this population, and the immune response is often less effective. This could therefore lower the effectiveness of the vaccine. The preliminary results announced by the two companies do not seem to indicate any significant differences by age, but these data remain to be validated.

We are therefore awaiting the publication of the complete results of the studies in peer-reviewed journals in order to be able to analyze the protection and security data in detail.

TC: The Pfizer and Moderna vaccines are based on a new technology, that of RNA vaccines, what are the specificities?

MPK: Most vaccines consist of the administration of a virus killed by chemical treatment, an unattenuated (non-pathogenic) form of this virus or a small part of it: it is therefore impossible to pathogen to reproduce. The goal is to prepare an effective immune response in case of contact with the "real" virus.

The technology of RNA vaccines is different: the idea here is to inject the genetic material of the virus, then our cells will be responsible for producing one or more viral proteins, which will be recognized by our immune system.




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A disadvantage of this technology is that the RNA molecule itself is fragile, which is why Pfizer recommends storing its vaccine at a temperature of -70 ° C. This therefore poses significant logistical problems, but I would remind you that freezers making it possible to reach these temperatures are classic tools in research laboratories, so it does not seem to me that in France, this is an insurmountable problem. For its part, Moderna has succeeded in developing a vaccine that is stable for several months at -20 ° C, and even 30 days at a refrigerator temperature (4 ° C), or even 12 hours at room temperature. We can hope that the technological developments implemented by BioNTech and Pfizer will in the future allow storage conditions similar to those announced by Moderna to be achieved.

TC: What do we know about vaccine safety?

MPK: At the moment, there is little security data. We nevertheless know the “reactogenicity” or how our body reacts to the injection of the vaccine: it is headache, pain or swelling in the arm, or even nausea. It is observed that mRNA vaccines are quite reactogenic, more for example than vaccines against influenza, this remaining acceptable.

What is still unknown are the longer-term side effects, which are bound to appear as the number of people vaccinated increases and over time.

The health authorities will be very attentive to this. In the United States, the FDA (Food and Drug Administration), for example, required that companies provide this data on at least half of the vaccinated cohort, or around 10 people, with at least two months of hindsight. This follow-up will of course continue, and we will have consolidated data approximately 000 months after vaccination.

TC: When can we expect to be put on the market?

MPK: It will take the green light from the health authorities. BioNTech / Pfizer and Moderna should be able to provide the FDA with this safety data at the end of November. One could therefore imagine that if no problematic element is identified, the marketing authorization will arrive in December.

For Europe, the equivalent of the FDA is the EMA (European Medicines Agency). The procedures and deadlines are similar. Once the authorizations have been issued, it will be up to manufacturers to be able to supply an enormous quantity of vaccines.

France has already signed agreements with some vaccine producers in order to have a portfolio of vaccines. The State has in fact preferred to invest in more than one technology rather than putting “all its eggs in one basket. "

The vaccinations could therefore begin in early January if everything goes as planned.

TC: Who will be vaccinated?

MPK: As a priority, we advocated to immunize caregivers, on a voluntary basis. It is above all an ethical obligation: let us help those who help us. Beyond this aspect, our healthcare system was put to the test during the two epidemic waves. It is therefore essential that the maximum number of personnel can be in good health to take care of the sick.

At the same time, it will be necessary to take care of the people most likely to trigger a serious form of the disease, so we are talking about the elderly (over 65 years), people under 65 years of age suffering from chronic pathologies (pathologies cardiovascular disease, hypertension, diabetes) and people with obesity. This represents around 25% of the French population.

Marie-Paule Kieny, Research Director, Inserm

This article is republished from The Conversation under Creative Commons license. Read theoriginal article.

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