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The Covid-19 vaccine developed by AstraZeneca and the University of Oxford causes an immune response in elderly people, particularly at risk, according to the results released Thursday which confirm announcements already made in October.
However, these interim results refer to a less advanced stage of development (called phase 2) than those that have been the subject of spectacular announcements over the past ten days by manufacturers BioNTech / Pfizer and Moderna.
They both ensured that their vaccine was 95% and 94.5% effective based on the results of the last phase of the clinical trials (Phase 3). These announcements have not yet been the subject of detailed publication in a scientific journal.
The results of phase 2 of the AstraZeneca / University of Oxford project were published on Thursday in the medical journal The Lancet.
Main lesson: This vaccine provokes an immune response in older people (over 56 years) identical to that it triggers in younger people (18 to 55 years old).
This observation is important because, as The Lancet reminds us, “the elderly have a ten times greater risk of developing a severe form of Covid-19, and it is therefore essential that a vaccine designed to fight this disease is effective in this population group. “.
“The immune response triggered by vaccines is often weaker in the elderly because the immune system gradually weakens over time,” said prof. Andrew Pollard, one of the leaders of the Oxford University trial.
The researchers note, however, a limit to their study. The mean age in the older group of participants ranged from 73 to 74, and few of them had health problems.
“It may therefore be that they are not representative of the entire elderly population, including people living in special institutions or who are over 80,” notes The Lancet.
These results must therefore be “confirmed within a larger sample of volunteers, including elderly people with health problems”: this is the goal of the Phase 3 trials currently underway for this vaccine, which affect thousands of people.
Phase 2 involved 560 participants (160 from 18 to 55, 160 from 56 to 59 and 240 over 70). They had been divided into different groups in which the vaccine or another product was administered, in order to be able to compare and evaluate the effectiveness of this.
For its part, the Pfizer / BioNTech alliance assured Wednesday that their vaccine was effective in people over the age of 65 according to Phase 3 results, which have yet to be confirmed by their publication.
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