While the pandemic has already claimed nearly 650,000 lives worldwide, the vaccine appears to be the only response to contain the virus and is launching an unprecedented race for drug companies around the world.
The major powers are in a hectic race to find a vaccine against Covid-19. A global competition with enormous economic efforts. But do not promises from some governments risk disappointing hopes? The state’s advances in vaccine research worldwide.
How many vaccine candidates?
In its last paragraph dated 24 July, the World Health Organization (WHO) lists 25 “vaccine candidates” evaluated in clinical trials on humans around the world (compared to 11 in mid-June). tests already underway, the WHO has counted 139 candidate vaccine projects in the pre-clinical development phase.
Good news. Because “the more vaccine candidates there are, and above all the more types of vaccine candidates there are, the greater the chances we have of achieving something”, explains AFP DanielFloret, Vice President of the Technical Commission on Vaccinations, affiliated to the French Higher Health Authority (HAS). ).
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Most of these experiments are still in the “phase 1” stage (which is mainly aimed at assessing the safety of the product), or in the next step, “phase 2” (where the question of efficiency).
Only four vaccine candidates are in the most advanced stage of “phase 3”, where efficacy is measured on a large scale. The latest is the American company Moderna, which began on Monday this last phase, during which it will be tested on 30,000 volunteers.
Two Chinese projects have entered Phase 3 since mid-July: the one from Sinopharm Laboratory, tested in the United Arab Emirates with a target of 15,000 volunteers, and the one from Sinovac Laboratory, tested on 9,000 medical staff in Brazil, in collaboration with Brazilian Research Institute Butantan.
The fourth project in phase 3 is European. Led by the University of Oxford, in collaboration with AstraZeneca, it is being tested in the UK, Brazil and South Africa.
There are different approaches, either based on proven vaccine categories or on experimental techniques. Some teams work with classic types of vaccines that use a “killed” virus: these are the “inactivated” vaccines (like those from Sinovac and Sinopharm).
There are also so-called “subunit” vaccines, based on proteins (antigens) that trigger an immune response, without viruses.
Other so-called “virus vector” vaccines are more innovative: another virus is used as a carrier that is transformed and adapted to fight Covid-19. This is the technique chosen by the University of Oxford, which uses a chimpanzee adenovirus (a family of very common viruses).
Finally, other innovative projects based on “DNA” or “RNA” vaccines are experimental products that use pieces of modified genetic material. This is the case with Moderna.
The preliminary results of two vaccine candidates, those from the University of Oxford (for its Phases 1 and 2) and the results of a Chinese company, CanSino (for its Phase 2), were published on July 20 in the medical journal The Lancet: These results are considered encouraging. They show that the two vaccines elicit “a strong immune response”, which triggers the production of antibodies and T lymphocytes.
In addition, they are well tolerated by patients. No serious side effects were reported, the most common side effects were headache, fever, fatigue and pain at the injection site.
However, it is too early to draw any conclusions. “It is not yet clear if these levels of immunity can protect against infection. […], nor whether this vaccine can protect the most fragile of severe forms of Covid-19 “, commented Jonathan Ball, Professor of Molecular Virology at the University of Nottingham (UK), who did not participate in this research.
In addition, a British study released in mid-July suggests that antibody-based immunity may disappear in just a few months in the case of Covid-19, which may complicate the development of an effective vaccine in the long term. term.
Motin Tell Again Charges
All over the world, procedures have been accelerated in an outstanding way. This is especially true in China, a country that has seen the emergence of the SARS-CoV-2 virus and would like to be the first with a vaccine.
International fundraising has been launched by states and large foundations. This enables companies to set up the industrial process of manufacturing their vaccine while working on its development, usually two distinct steps.
Unlike Europe, the United States goes its own way. The Trump administration has set up Operation Warp Speed to accelerate the development of a vaccine primarily intended for 300 million Americans. To this end, the US government is investing in several horses at once and investing billions of dollars in various programs.
This cool race even gets the appearance of a spy novel. Britain, the United States and Canada have accused Russian intelligence services of being behind hacker attacks for stealing research on a vaccine. And in the United States, two Chinese have been prosecuted for similar reasons. Both Moscow and Beijing have denied the allegations.
“To approve a vaccine against Covid-19, clinical trials will need to provide a high level of evidence of its safety, efficacy and quality,” warned the European Medicines Agency (EMA).
Because going too fast in clinical trials “can be a problem” in terms of safety, DanielFloret emphasizes. According to him, “one of the most important points will be to provide evidence that the vaccine is not likely to cause an exacerbation of the disease”, that is, to make it more serious in vaccinated people, contrary to the objective.
It happened in monkeys “while trying to develop vaccines against MERS-CoV and SARS”, two other coronaviruses. In humans, this phenomenon of exacerbation of the disease was also observed in the 1960s, with some vaccines against measles, which has been withdrawn, and against infantile bronchiolitis, which has been abandoned, the expert recalls.
A vaccine against autumn … or never
EMA believes “it may take at least until early 2021 for a Covid-19 vaccine to be ready for approval and available in sufficient quantity[pour un usage mondial]”.
But the most optimistic, from some pharmaceutical companies, assure that it is possible from this autumn. “I’m not sure it is very realistic to say that we will get a vaccine in the autumn, we must temper this enthusiasm,” said PrFloret, who “expects the best in the first quarter of 2021.”
“If we get there by that time, it will already be a hell of a miracle,” while it usually takes several years. And in the worst case, it is still possible that we will never succeed in developing a vaccine. .
Confidence in vaccines
Even if the research succeeds in the short or long term, one last, important question will remain: will people accept being vaccinated, in the context of growing mistrust of vaccination?
“As the repeated measles outbreaks show, we have not been very good at addressing people’s concerns about vaccines. And if we do not learn from these mistakes, some coronavirus vaccination programs are doomed.” Advances, “warned a U.S. pediatrician, PhoebeDanziger new column published by the New York Times.
“Vaccine development is only part of the solution. Broad approval of these vaccines is also needed,” US experts from Johns Hopkins University and Texas State University said in a report. report in early July.