AFP, published on 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 before the approval of the authorities, according to the World Health Organization. Update on these candidates, likely to arrive on the market first.
– “Messenger RNA”, at the forefront:
At present, it is the potential vaccines that appear to be the most advanced, using ultra-innovative technology. It consists in injecting into our cells strands of genetic instructions called messenger RNA, to make them manufacture specific proteins or “antigens” of 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 which could be available before the end of the year. The companies presented interim results from phase 3 a few days ago showing “over 90%” effectiveness in participants.
– Moderna: the American biotechnology company announced Monday that its vaccine was 94.5% effective, it plans to manufacture 20 million doses by the end of the year.
– The well-known inactivated virus technology:
Several vaccines rely on this technology: the infectious agents of SARS-CoV-2 are treated chemically or by heat to lose their harmfulness, while retaining their ability to provoke an immune response. It is the most traditional form of vaccination.
– Sinovac: Chinese biotech has started 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 plans to be in capacity by the end of the year to produce 610 million doses per year of several Covid-19 vaccines, and has already given the green light for emergency use of some of them.
– The 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 relies on a vaccine available in the first half of 2021.
– Viral vector vaccines:
Viral vector vaccines use another weakly virulent virus as a carrier, transformed to add part of the virus responsible for Covid-19. The modified virus enters the cells of vaccinated people, who then make a protein typical of Sars-Cov-2, educating their immune system 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 launched two clinical trials of its candidate consisting of a modified adenovirus, one single-dose, the other over two doses. Around the world, 90,000 participants will take part in total. Results expected in the first quarter of 2021.
– CanSino Biological: the Chinese company has developed “Ad5-nCoV”, jointly 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 Defense Ministry, 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 with the usual protocols to accelerate the scientific process. Several senior Russian officials announced that they had already been vaccinated with Sputnik V.
– A recombinant protein vaccine:
– Novavax: the American biotech is developing a so-called “subunit” recombinant vaccine. The coronavirus has spikes (viral proteins) on its surface to come into contact with the cells to be infected. These proteins can be replicated and then presented to the immune system to make it react. Novavax launched its phase 3 trial in the United Kingdom in September, and is due to start a trial in the United States at the end of November. Preliminary data is expected in the first quarter of 2021.