Paris | global Competition the financial stakes are enormous, the quest for a vaccine against the COVID-19 advance at an unprecedented rate. But beware of the effects of the announcement and hopes disappointed.
How many vaccines?
In his last point, dated July 24, WHO lists 25 ” candidate vaccines evaluated in human clinical trials around the world (up from 11 in mid-June).
Most of these trials are still at the stage of “phase 1” (which aims primarily to evaluate the safety of the product), or to the next step, the “phase 2” (where it is already exploring the question of the effectiveness).
Only four candidate vaccines are at the stage the more advanced “phase 3”, where efficiency is measured on a large scale. The last in date is that of the american society Moderna, which started Monday, this is the ultimate phase during which it will be tested on 30 000 volunteers.
Two chinese projects entered phase 3 since mid-July: the laboratory Sinopharm, tested in the united arab Emirates with a goal of 15,000 volunteers, and the laboratory Sinovac, tested on 9000 health professionals in Brazil, in partnership with the research institute of the brazilian Butantan.
The fourth project in phase 3 is european. Conducted by the University of Oxford, in cooperation with the company AstraZeneca, it is tested in the United Kingdom, Brazil, and South Africa.
In addition to the testing already started, WHO accounts for 139 projects of vaccine candidates in the preclinical phase of development.
What techniquesIl there are different approaches, based either on the categories of vaccines, proven or experimental techniques.
Some teams are working on different types of vaccines that use a virus ” killed “: what are the vaccines “inactivated” (such as those of Sinovac and Sinopharm).
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 a other virus that transforms and adapts to fight the COVID-19. This is the technique chosen by the university of Oxford, which uses an adenovirus (a family of viruses very common) chimpanzee.
Finally, other innovative projects are based on vaccines, ” DNA ” or ” RNA “, of the experimental products using pieces of genetic material altered. This is the case of the Moderna.
“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?
The preliminary results of two vaccine candidates, one from the university of Oxford (for its phase 1/2) and that of a chinese company, CanSino (for phase 2), are published on 20 July in the medical journal the Lancet.
These results are considered encouraging. They show that both vaccines induce a strong immune response “, by triggering the production of antibodies and t lymphocytes.
In addition, they are well tolerated by the patients. No serious adverse effects were recorded, the most frequent side effects being headache, fever, fatigue, and pain at the vaccine injection site.
For many, it is far too early to draw conclusions.
“It is not yet known if these levels of immunity can protect against infection ( … ), nor whether this vaccine can protect the most fragile of the serious forms of Covid-19 “, commented Jonathan Ball, professor of molecular virology at the university of Nottingham (United Kingdom), who was not involved in this research.
In addition, a british study made public in mid-July suggests that the immunity based on the antibodies may disappear in only a few months in the case of the COVID-19, which may complicate the development of an effective vaccine in the long term.
Everywhere in the world, the procedures were accelerated in an unprecedented way. This is particularly true in China, a country that has seen the emergence of the virus SARS-CoV-2 and wants to be the first to have a vaccine.
Fundraising international have been launched by States and large foundations. This allows companies to put in place the industrial process of manufacturing of their vaccine at the same time that they are working on its development, two stages usually separate.
On their side, unlike Europe, the United States alone.
The administration Trump has launched the operation “Warp Speed” (” beyond the speed of light “) to accelerate the development of a vaccine for use in priority to all 300 million Americans.
For this, the u.s. government is betting on several horses at the same time and has invested billions of dollars in various programs.
This race takes even like a spy novel. The United Kingdom, the United States and Canada have accused the intelligence services of the Russian of being behind the attacks carried out by hackers to do hands on research on a vaccine. And in the United States, two Chinese were charged for similar reasons.
Moscow, like Beijing, have swept these allegations.
“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 in the worst scenarios, it is still possible that we never get to bring a vaccine to the point.
Crisis of confidence?
Even if the research resulted in a more or less long term, 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, ” said a pediatrician american, Phoebe Danziger, in a recent op-ed published by the New York Times.
“The development of vaccines is only one part of the solution. A wide acceptance of these vaccines is also necessary “, have abounded of american experts from Johns Hopkins university and the university of the State of Texas in a report in early July.