Paris | The quest for a vaccine against the COVID-19, it is the equivalent of ” around the world in 80 days “: a race to global faster than ever, with huge financial stakes. But beware of the effects of announcement, hopes disappointed, and security problems, warn experts.
How many vaccines?
In his last point, dated 6 July, WHO identifies 21 ” candidate vaccines evaluated in human clinical trials around the world (up from 11 in mid-June).
The third of these trials is made in China. This country, which has seen the emergence of the virus SARS-CoV-2, wants to be the first to have a vaccine, and does not hesitate to multiply the proceedings accelerated.
Most of the current trials are still in the stage called phase 1, which aims primarily to evaluate the safety of the product, or even in phase 2 (where you can already explore the question of the effectiveness).
Two of the candidates are the highest stage, phase 3, where the efficiency is measured on a large scale: the european project of the University of Oxford, in cooperation with the company, AstraZeneca, and the chinese, the laboratory, Sinovac, in partnership with the research institute of the brazilian Butantan.
In addition to the testing already started, WHO accounts for 139 projects vaccine candidates that are in pre-clinical phase of development.
There are different approaches, with categories of vaccines, proven or, on the contrary, experimental.
Some teams are working on different types of vaccines that use a virus that was “killed” (these are the type vaccines ” inactivated “) or made less virulent (the ” live-attenuated “).
There are also vaccines that are called ” sub-unit “, with a base of proteins (antigens) that trigger an immune response, virus-free.
Other vaccines, called ” viral vector “, are more innovative: it uses as a support or another virus (e.g. measles, such as the Pasteur Institute) that transforms and adapts to fight the COVID-19.
Finally, other innovative projects relate to vaccines ” DNA ” or ” RNA “, of the experimental products using pieces of genetic material altered.
“The more vaccine candidates, and more importantly, there are types of vaccine candidates, the more chances we have to achieve something “, explains to the AFP Daniel Floret, vice-president of the technical Committee of the vaccinations, which is attached to the High authority of health (HAS) French.
What are the results?
For the moment, only partial results were made public, some described as “encouraging” by the firms.
“There are effects of ad considerable industry pharmaceutical, that it must look with great caution,” says the AFP immunologist Jean-François Delfraissy, president of the scientific Council to guide the French authorities during the pandemic.
“An injection of the vaccine in 30 people that we are told as a result, well this is not a result “, he adds.
Releases of firms are intended “to provide information to the public” but also “to Exchange” and ” it is never neutral “, abounds the Pr Floret. “It is important that they show us that they are trying to speed things up, but it will still be necessary to see the results, and for the moment, we do not see “.
Quickly and well?
Everywhere in the world, the procedures were accelerated in an unprecedented way.
“It’s moving very quickly (…) and the projects are maybe even a little faster than had been expected “, tells the AFP Christophe d Enfert, of the Pasteur Institute.
Fundraising international have been launched by States and large foundations, even if the United States goes it alone, unlike Europe and other countries.
The administration Trump has launched the operation “Warp Speed” (” beyond the speed of light “) in an attempt to produce 300 million doses of a vaccine by January 2021, in order to vaccinate in priority the American.
The companies “are trying to develop a vaccine and, at the same time, to put in place the industrial process for the manufacture, while, in general, we expect this to have results,” explains the Pr Delfraissy.
“That is why they request funding in the country, saying: we take the risk of starting on a vaccine that will work maybe not and if we put the industrial process in the road, we need to be partly covered by international funding,” says he.
“To authorize a vaccine against the COVID-19, it will be necessary that clinical trials provide a high level of evidence on its safety, efficacy, and quality “, has notified the european medicines Agency (EMA).
Because to go too fast in the clinical trials “can be problematic” in terms of safety, stresses Daniel Floret.
According to him, ” one of the key points that will provide evidence that the vaccine is not likely to result in an exacerbation of the disease “, that is to say, to make it more severe among vaccinated persons, the opposite of the goal.
It happened on of the apes ” in attempts to develop vaccines against MERS-CoV and SARS “, two other coronaviruses.
In humans, this phenomenon of worsening of the disease was also observed in the 60s with some vaccines against measles, which were removed, and against the bronchiolitis of the infant that has been abandoned, recalls the expert.
When a vaccine?
The EMA considers “that it could take at least until the beginning of 2021 for a vaccine against the COVID-19 is ready to be approved and available in sufficient quantity” for use anywhere in the world.
But the more optimistic, starting with some pharmaceutical companies, to ensure that it is possible as early as this fall.
“I’m not sure that this is very realistic to say that we will have a vaccine in the fall, it is important to temper this enthusiasm “, says the Pr Floret, that ” table on the first quarter of 2021 “.
“If it gets to that deadline, this will already be a hell of a prodigy “, while it usually takes several years.
And if it never happened?
The world waits for a vaccine as the Messiah, or, in any case, as the only surefire way to put an end to the pandemic of Covid-19. But is it possible that we never found?
“It is not won in advance “, concedes the Pr Delfraissy. “No one has ever developed a vaccine against a coronavirus, even if it is never given completely the means.”
“There is a certain degree of uncertainty on our ability to develop a vaccine against a coronavirus, but in any case, all the ingredients for success are in place “, he adds.
“Everything is possible, but there, a maximum of means have been set, a maximum of different techniques being considered and it would still be surprising that you can’t do it “, advance the Pr Floret.
But even if the research proves successful, it will continue to be a ultimate issue, of size: the people will they agree to be vaccinated, in a context of distrust growing towards the vaccination?
“As shown by the repetition of the outbreaks of measles, we have not been very good to respond to the concerns of the people about vaccines. And if we do not learn from these errors, any program of vaccination against coronavirus is condemned “, is afraid of a pediatrician american, Phoebe Danziger, in a column published Thursday by the New York Times.