The vaccine against Covid-19 developed by AstraZeneca and Oxford University provokes an immune response in older people, who are particularly at risk, according to results published Thursday.
The results of AstraZeneca - Oxford’s phase 2 clinical trials were published in The Lancet, a medical journal.
The main finding of the phase 2 clinical trials is that the vaccine provokes an immune response in the oldest subjects (over 56 years old) that is identical to the one it triggers in the youngest (18 to 55 years old).
This is important because older adults have a tenfold risk of developing a severe form of Covid-19, as The Lancet said.
The immune response triggered by vaccines is often weaker in older adults as "the immune system gradually deteriorates with age," explained Professor Andrew Pollard, one of the trial leaders from Oxford University.
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However, the researchers noted a limitation to their study. The average age in the oldest group of participants was between 73 and 74 years old and few of them had health problems.
As a result, the data "might not be representative of the general older population, including those living in residential care settings or older than 80 years," the study noted.
"Larger studies are now underway to assess immunogenicity, safety, and efficacy in older adults with a wider range of comorbidities," the authors said.
That brings them to Phase 3 clinical trials, a stage already reached by Pfizer-BioNTech and Moderna. The results of both of those studies are promising as well, showing effectiveness rates of 95% and 94.5% respectively.
AstraZeneca's phase 2 involved 560 participants (160 aged 18-55, 160 aged 56-59 and 240 over 70). They were divided into several groups where they were given either the vaccine or another product to compare and evaluate the effectiveness of the vaccine.
AstraZeneca was the first to strike a deal with the European Commission on a future vaccine, signing a contract on 27 August. In the meantime, five such contracts have been signed, the others being with Sanofi and GSK, Janssen Pharmaceutica, BioNTech and Pfizer and, as of Wednesday, CureVac.
The Commission is also in "successful exploratory talks" with Moderna, it said on Wednesday.
Jason Spinks
The Brussels Times
