The mad race for the vaccine against the Covid-19 around the world

The great powers are in a frantic race to find a vaccine against Covid-19. A planetary competition with enormous financial stakes. But do the promises made by certain governments not risk feeding dashed hopes? State of progress in vaccine research around the world. 

How many vaccine candidates?  

In its last point dated July 24, the World Health Organization (WHO) lists 25 "vaccine candidates" evaluated in clinical trials on humans around the world (against 11 in mid-June). In addition to the trials already started, the WHO has counted 139 candidate vaccine projects in the pre-clinical development phase.  

Good news. Because "the more there are candidate vaccines, and especially the more there are types of candidate vaccines, the more likely we are to achieve something", explains to AFP Daniel Floret, vice-president of the Technical Commission vaccinations, attached to the French High Authority for Health (HAS). 

>> To read: Covid-19: a vaccine tested in South Africa, a first on the continent

Most of these trials are still at the "phase 1" stage (which aims above all to assess the safety of the product), or at the next stage, "phase 2" (where the question of efficiency). 

Only four vaccine candidates are at the most advanced stage of "phase 3", where efficacy is measured on a large scale. The latest is that of the American company Moderna, which began on Monday this final phase during which it will be tested on 30,000 volunteers. 

Two Chinese projects have entered phase 3 since mid-July: that of the Sinopharm laboratory, tested in the United Arab Emirates with a target of 15,000 volunteers, and that of the Sinovac laboratory, tested on 9,000 healthcare professionals in Brazil, in partnership with the Brazilian research institute Butantan. 

The fourth project in phase 3 is European. Led by the University of Oxford, in cooperation with the company AstraZeneca, it is being tested in the UK, Brazil and South Africa. 

What techniques?  

There are different approaches, based either on proven vaccine categories or on experimental techniques. Some teams are working on conventional types of vaccines which use a "killed" virus: these are the "inactivated" vaccines (such as those from Sinovac and Sinopharm). 

There are also so-called "subunit" vaccines, based on proteins (antigens) that trigger an immune response, without viruses. 

Other vaccines, known as "viral 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 are based on "DNA" or "RNA" vaccines, experimental products using pieces of modified genetic material. This is the case with Moderna's. 

What results? 

The preliminary results of two vaccine candidates, that of the University of Oxford (for its phase 1 and 2) and that 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", triggering the production of antibodies and T lymphocytes. 

In addition, they are well tolerated by patients. No serious side effects were recorded, the most common side effects being headache, fever, fatigue and pain at the injection site. 

However, it is far too early to draw any conclusions. "It is not yet known whether these levels of immunity can protect against infection […], nor if 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 (United Kingdom), which did not participate in this research. 

In addition, a British study released in mid-July suggests that antibody-based immunity could 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. 

Counterintelligence charges 

All over the world, procedures have been speeded up in unprecedented ways. This is particularly true in China, a country which has seen the emergence of the SARS-CoV-2 virus and would like to be the first to have a vaccine. 

International fundraising has been launched by states and large foundations. This allows companies to set up the industrial process for manufacturing their vaccine at the same time as they work on its development, usually two distinct stages. 

For its part, unlike Europe, the United States is going it alone. The Trump administration has set up Operation Warp Speed ​​to accelerate the development of a vaccine intended primarily for 300 million Americans. For this, the US government is betting on several horses at the same time and has invested billions of dollars in various programs. 

This frantic race even takes on the appearance of a spy novel. The UK, US and Canada have accused Russian intelligence services of being behind hacker attacks to steal research into a vaccine. And in the United States, two Chinese have been indicted on similar grounds. Both Moscow and Beijing brushed aside these accusations. 

Too fast ? 

"To authorize a vaccine against Covid-19, clinical trials will need to provide a high level of evidence on its safety, efficacy and quality," warned the European Medicines Agency (EMA). 

Because going too fast in clinical trials "can pose a problem" in terms of safety, underlines Daniel Floret. According to him, "one of the key points will be to provide proof that the vaccine is not likely to lead to an exacerbation of the disease", that is to say to make it more serious in those vaccinated. , the opposite of the objective. 

It happened in monkeys "during 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 1960s, with certain vaccines against measles, which were withdrawn, and against infantile bronchiolitis, which was abandoned, recalls the expert. . 

A vaccine for the fall ... or never  

The EMA believes "it could take at least until early 2021 for a Covid-19 vaccine to be ready for approval and available in sufficient quantity [for global use]". 

But the most optimistic, starting with certain pharmaceutical companies, assure that it is possible as of this fall. "I am not sure that it is very realistic to say that we will have a vaccine in the fall, we must temper this enthusiasm ", judges Professor Floret who" expects the best on the first quarter of 2021 ". 

"If we get there at that time, it will already be a hell of a miracle", whereas it usually takes several years. And in the worst-case scenario, you may never be able to develop a vaccine. 

Distrust of vaccines 

Even if the research succeeds sooner or later, there will remain one final, sizeable question: will people agree to be vaccinated, in a context of growing mistrust of vaccination? 

“As the recurring measles outbreaks show, we haven't been very good at addressing people's concerns about vaccines. And if we don't learn from these mistakes, any coronavirus vaccination program is doomed. 'advance,' warned American pediatrician Phoebe Danziger in a recent column published by the New York Times. 

"Vaccine development is only part of the solution. Broad acceptance of these vaccines is also needed," US experts from Johns Hopkins University and Texas State University said in a report. report early July. 

With AFP

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