Covid-19 vaccine: campaigns have been launched, questions remain - France 24

Paris (AFP)

With the green light granted by European health authorities at the beginning of the week, vaccination campaigns can begin as early as Sunday in continental Europe, after England, the United States and several Latin American countries.

Only one year after the onset of Covid-19, its antidote is available, but questions remain.

- How many vaccines?

The development and marketing of a new vaccine usually takes ten years on average, a period reduced to less than a year for Covid-19 thanks to the acceleration of research procedures, industrial production and evaluation, supported by colossal funding.

The United Kingdom gave the first green light on December 2 to the vaccine developed by the American Pfizer and the German BioNTech.

Since then, tens of thousands of elderly and health workers have received their first dose.

In the United States, emergency authorizations have been granted by the American Medicines Agency (FDA) to Pfizer / BioNTech and the American Moderna.

A total of 16 countries and the European Union have given the green light to the Pfizer / BioNTech vaccine.

For its part, Russia started its campaign on December 5 with the Russian vaccine Sputnik V, still in its third and final phase of clinical trials.

And Chinese authorities have already given the green light for emergency use of some of their vaccines, although none have yet been formally approved.

In total, 16 vaccines are in the last stage of development, phase 3, according to the latest WHO point, a count including those already on the market.

- What timetable for the European Union?

The European Medicines Agency (EMA) on Monday gave the green light for the marketing of the Pfizer / BioNTech vaccine and the European Commission said the vaccination campaign could start on Sunday.

From the date of this marketing authorization, each member country takes control of defining priority audiences and logistics organization.

In France, the first vaccinations will take place on Sunday.

- What is the best vaccine?

Since November 9, four manufacturers have announced that their vaccine is effective: Pfizer / BioNTech, Moderna, the British alliance AstraZeneca / University of Oxford, and the Russian state institute Gamaleïa.

These announcements are based on the last stage of clinical trials, phase 3, for which tens of thousands of volunteers have been recruited.

But detailed and validated scientific data is only available for two of them: those from Pfizer / BioNTech and AstraZeneca / Oxford.

The scientific journal The Lancet confirmed on December 8 that AstraZeneca's vaccine was 70% effective on average.

For the Pfizer / BioNTech vaccine, the US Medicines Agency (FDA) confirmed in a report on the trial data the very high 95% efficacy of the vaccine, administered in two doses three weeks apart.

Moderna boasts a very close efficiency of 94.1%.

The Russian Sputnik V vaccine, for its part, displays an effectiveness of 91.4% on its 39 patients (and 95% on an unspecified number of patients).

The AstraZeneca / Oxford vaccine has for him to be the cheapest (around 2.50 euros per dose).

Those from Moderna and Pfizer / BioNTech have a logistical handicap, because they can only be stored long term at very low temperature (-20 ° Celsius for the first, -70 ° C for the second).

- What side effects?

Experts stress that with clinical trials carried out on tens of thousands of volunteers, a major safety problem has already been detected.

But side effects that are rarer or only occur in certain patient profiles cannot be ruled out.

According to the FDA report on the Pfizer / BioNTech vaccine, the latter often causes painful reactions when injected into the arm (in the order of 80%).

Adverse effects such as fatigue, headaches and muscle stiffness follow, more rarely fever.

- What other outstanding questions?

The most important is that of long-term efficacy, since so far it has been calculated only one to two weeks after the last injection.

"How long will the protection last? Will the virus eventually mutate to escape the vaccine, which would then limit the effectiveness of the vaccination?", Summarizes a British expert, Penny Ward (King's College of London), cited by Science Media Center (SMC).

Another crucial question: it is not known whether the action of these vaccines is the same in the populations most at risk, starting with the elderly, who are more likely to develop a severe form.

It also remains to be seen whether these vaccines block the transmission of the virus, in addition to reducing the severity of the disease in those who have received them.

- A less effective vaccine against the variant detected in the United Kingdom?

Experts from the European Union believe that the current vaccines against Covid-19 remain effective against the new strain of the virus detected in the United Kingdom, presented as more contagious by the British.

"At the moment there is no evidence to suggest" that the Pfizer / BioNTech vaccine "is not effective against the new variant," said the European Medicines Agency.

A message repeated by the co-director of the German BioNTech laboratory, Ugur Sahin, who also assured that his company was able to deliver a new vaccine in six weeks.

© 2020 AFP