What are the different types of vaccine developed against Covid-19?

A vaccine research center in the United States (illustrative image).

-

• While the WHO on Sunday recorded a new record of contamination in the world, with 660,905 new cases in 24 hours, the vaccine race is on.

• 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 technique of vaccination, used until then in research against cancer and in animal health.

  " 20 minutes "

  explains everything to you.

"If we have several vaccines, we will choose those which seem to us to be the safest and the most effective", said Sunday the Minister of Health Olivier Véran.

Faced with the Covid-19 epidemic, the vaccine race appears to be an immense hope, as encouraging new studies were published on Monday concerning the Moderna vaccine.

The opportunity to learn that all vaccines are not made from 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 in Europe. 

 takes stock of the five major types of virus vaccines.

And among them, those that will be used tomorrow against the pandemic.

The new kid on the block: 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 on pig farms, recalls Futura Sciences.

It involves injecting strands of genetic instructions called messenger RNA into the body, which tell our cells what to make to fight the coronavirus.

Strong point: 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 that of Pfizer / BioNTech, which can be a major logistical brake for their distribution around the world.

“The genetic code degrades very quickly at high temperatures.

A vaccine that directly contains the virus can be stored at less cold temperatures, ”

Judith Mueller, professor at EHESP and researcher at the Pasteur Institute

, explains to

.

Last Thursday, Olivier Véran assured that France had equipped itself with 80 super-freezers for this purpose.

Another obstacle to this vaccine: it requires two doses, only one is not sufficient to provide a sufficient immune response.

Note that this technique is also developed in cancer research.

The peaks of Covid-19 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 spike protein of the coronavirus (the characteristic peaks of the virus) will be associated with another virus, of the adenovirus type (Chimpanzee cold virus for example, very well known and harmless to humans ) in order to trigger a stronger immune response.

“These thorns that come out of the virus are easily accessible to the immune system.

They play a very specific role in the virulence of the epidemic.

It ensures a good immune reaction of the body ”, assures Judith Mueller.

Flu, Polio and ... Covid-19: Inactivated vaccines

"We take the virus itself and we make a preparation, which we inactivate by chemical means, heat or physical process, such as exposure to UV for example," explains Professor 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 laboratory Sinopharm 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 retain its ability to multiply, but at very low noise," says Professor Schwartz.

The virus, which is not pathogenic, multiplies in the body, which is then exposed to the virus for a period of time.

"It induces a good response of the immune system," 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 laboratory Sanofi.

As to which of these vaccines will be the most effective against the coronavirus, it is impossible today.

“The current results are very encouraging but they are still preliminary.

Vaccinology is an experimental science, you have to test to find out which strategy will work, ”concludes Professor Schwartz.

Health

Coronavirus: Planes, dry ice, pharmacies… The formidable logistical challenge of vaccination

Health

Coronavirus: Should a future vaccine against Covid-19 be made compulsory?

• Health

• Covid 19

• Coronavirus

• Vaccination

• Vaccine