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AFP, published Wednesday 18 November 2020 at 08:24
Faced with Covid-19, 48 vaccine candidates are currently in clinical trials on humans. But only eleven have entered phase 3, the last one before the approval of the authorities, according to the World Health Organization. Update on these candidates, which are likely to arrive first on the market.
– “Messenger RNA”, first in line:
Currently, it is the potential vaccines that appear to be the most advanced, using ultra-innovative technology. It consists of injecting strands of genetic instructions called messenger RNA into our cells to make them produce proteins or “antigens” specific to the coronavirus. These proteins will be delivered to the immune system, which will then produce antibodies.
– Pfizer: the American giant and its German partner BioNTech are preparing to ask the American Medicines Agency for an authorization for emergency use, for a vaccine that could be available by the end of the year. The companies presented interim results from Phase 3 a few days ago that show “over 90%” effectiveness in the participants.
– Modern: The American biotech company announced Monday that its vaccine was 94.5% effective, expecting to produce 20 million doses by the end of the year.
– The known technology of inactivated viruses:
Several vaccines rely on this technology: SARS-CoV-2 infectious agents are chemically or heat treated to lose their harmfulness, while retaining their ability to provoke an immune response. It is the most traditional form of vaccination.
– Sinovac: Chinese biotechnology has launched a phase 3 trial for “CoronaVac” on thousands of volunteers, particularly in Brazil.
– Sinopharm, another Chinese laboratory, has for its part launched two vaccine projects with Chinese research institutes. China expects to be able to produce 610 million doses per year of different Covid-19 vaccines by the end of the year and has already given the green light for emergency use of some of them.
– Indian company Bharat biotech, for its part, launched in November the recruitment of nearly 26,000 people for its “COVAXIN” developed with the support of the Indian government, and is relying on a vaccine available in the first half of 2021.
– Vector viral vaccines:
Viral vector vaccines use another weakly virulent virus as a vector, transformed to add part of the virus responsible for Covid-19. The modified virus enters the cells of vaccinated people, which then produce a protein typical of Sars-Cov-2, educating their immune systems to recognize it.
– AstraZeneca, an Anglo-Swedish group, and the University of Oxford: their vaccine uses an adenovirus as a viral vector. The results of the trial are expected this year.
– Johnson & Johnson: the American has started two clinical trials of his candidate consisting of a modified adenovirus, one single dose, the other over two doses. Around the world, a total of 90,000 attendees will participate. Results expected in the first quarter of 2021.
– CanSino Biologico: the Chinese company has developed “Ad5-nCoV”, together with the army, an adenovirus-based vaccine. Phase 3 trials are launched in Mexico, Russia and Pakistan.
– Sputnik V: developed by the Gamaleïa Epidemiology Research Center, with the Russian Ministry of Defense, it is based on the use of two viral vectors, two adenoviruses. The Russians announced a 92% efficiency a few days ago. However, the Gamaleïa Institute is accused of breaking the normal protocols to speed up the scientific process. Several senior Russian officials have announced that they have already been vaccinated with Sputnik V.
– A recombinant protein vaccine:
– Novavax: American biotechnology is developing a so-called “subunit” recombinant vaccine. The coronavirus has spikes (viral proteins) on its surface to make contact with the cells to be infected. These proteins can be reproduced and then presented to the immune system to make it react. Novavax started its Phase 3 trial in the UK in September and is expected to start a trial in the US in late November. Preliminary data are expected in the first quarter of 2021.
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