Two clinical trials, British and Chinese, showed a strong immune response and are well tolerated by patients. Larger-scale tests will be carried out before, if their effectiveness is confirmed, considering marketing.
- Both projects showed good immune response and no adverse side effects.
- The two trials will move into phase 3 clinical trials to test the efficacy of the candidate vaccines on a larger number of patients.
- Jean-François Delfraissy, the president of the scientific council, remains cautious even after the publication of these results.
The race for the Covid-19 vaccine is accelerating and two tracks seem to be taking the lead. These trials, the results of which were published in the journal The Lancet, are still preliminary but are encouraging. Both projects are based on an adenovirus, a family of very common viruses that cause colds in particular, which have been genetically modified to produce the so-called spike protein of SARS-CoV-2. The results relate to phase 2 clinical trials, which are testing tolerance and the onset of an immune response after injection of the vaccine, compared to a placebo. Phase 3 of the tests will be initiated. It aims to test their effectiveness on a larger number of participants. If this proves effective, commercialization may be considered.
A very strong immune response, no adverse effects
The British project is developed by researchers from the University of Oxford (United Kingdom), in partnership with the pharmaceutical industry AstraZeneca. The vaccine, tested on more than 1,000 patients, has been shown to create a good immune response by producing antibodies and T cells.”If our vaccine proves effective, it is a promising option, as this type of vaccine can be easily manufactured on a large scale.”, advances Sarah Gilbert, researcher at the University of Oxford. “It is not yet known whether these levels of immunity can protect against infection (…) nor if this vaccine can protect the most fragile from severe forms of Covid-19”, commented Jonathan Ball, professor of molecular virology at the University of Nottingham (United Kingdom), who was not involved in the study.
This is very positive news. A huge well done to our brilliant, world-leading scientists & researchers at @UniofOxford.
There are no guarantees, we’re not there yet & further trials will be necessary – but this is an important step in the right direction.https://t.co/PRUTu8rlPF—Boris Johnson #StayAlert (@BorisJohnson) July 20, 2020
On the Chinese side, the project, developed in Wuhan, where the pandemic started, is being carried out by researchers from several organizations and financed by the Hong Kong-listed biotechnology group CanSino Biologics. Phase 2 of the clinical trial involved 500 patients and again showed a double immune response against Covid-19. No adverse effects were observed. A month after the injection of the vaccine candidate, 85% of the candidates presented neutralizing antibodies in the blood, against 90% for the British study. The Chinese trial is the only one to have patients over 55, in whom the antibody levels observed were lower. “It is possible that an additional dose [de vaccin] is needed to elicit a stronger immune response in the elderly population”, estimated one of the authors, Wei Chen, of the Beijing Institute of Biotechnology.
In France, the Institut Pasteur has launched phase 1
Jean-François Delfraissy, the president of the scientific council, wanted to play the card of caution in the face of these promising results which give rise to hope. “Pay close attention to these announcements. The pharmaceutical industry, it’s normal, wants to push the advances that can happen. These are still announcement effectshe reacted to the microphone ofEuropean 1Monday evening. It is normal for there to be an immune response, but we do not yet know what kind, how strong, how long, and what types of antibodies are present. I am extremely careful. We are going to go faster than usual for a vaccine against the coronavirus, but we are rather in a strategy for the end of the year 2020 or the beginning of 2021.”
Among the other vaccine projects in the running, the American biotech Moderna also seems to be well advanced. Last week, it announced that it would launch phase 3 of its vaccine candidate on July 27. This will concern 30,000 people, half of whom will receive a placebo. In France, it is the Pasteur Institute that holds the rope for research. The vaccine candidate, based on a strain of measles, is tested on 90 volunteers during the month of July. If this is conclusive, phases 2 and 3 should be launched at the same time to save time and could start in October. If this vaccine candidate proves effective and safe, commercialization could occur in the first quarter of 2021.
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