The AstraZeneca vaccine shows encouraging results in older people

Hope in the face of the epidemic. AstraZeneca and the University of Oxford said their Covid-19 vaccine elicits a good immune response in older people, particularly at risk of the virus. New results that confirm announcements already made in October.

These interim results, however, relate 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. 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.

A population at risk

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 mentioned The Lancet, “Older people have a ten times greater risk of developing severe 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.

Results to be confirmed

The researchers note, however, a limit to their study. The median age in the older group of participants ranged from 73 to 74, and few of them had any health problems. “It could therefore be that they are not representative of the entire elderly population, including people living in specialized facilities or those over 80,” he 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 ongoing phase 3 trials for this vaccine, which cover 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 where the vaccine or another product was administered, so that they could 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.