The Covid-19 vaccine currently being developed by the University of Oxford together with the Anglo-Swedish pharmaceutical company AstraZeneca produces a "strong immune response" in adults who are over 65 years old, according to data from the second phase of the clinical trial, published on Thursday in The Lancet. This announcement is important because generally older people tend to respond worse to vaccines than younger people.
The results of this second phase, based on the analysis of 560 cases - 240 of which were in people over 70 - suggest that the vaccine may provide high levels of immunity for those who are at a high risk of death or serious illness from coronavirus infection. The researchers say that "trial volunteers show similar neutralizing antibodies and T-cell responses in all three age groups (18-55, 56-69, and +70)" in which participants were classified.
The announcement comes one day after the US giant Pfizer and German biotech company BioNTech reported that their coronavirus vaccine is 95% overall effective, and 94% effective amongst adults over 65. These results are virtually equal to those presented by Moderna on Monday .
This could lead the public opinion to erroneously believe that the promoters of this vaccine have rushed the Phase II data, so as not to be left behind in the wild global race the pharmaceutical industry is currently in. However, unlike the research findings released by Pfizer-BioNTech and Moderna, AstraZeneca and Oxford University have published theirs so through a reputable publication and not in press releases.
No safety issues
Additionally, researchers at the Jenner Institute have not identified any serious safety problems. The evaluation of the Phase III clinical trial data - which are those Pfizer-BioNTech and Moderna are currently working with - is still ongoing. The promoters indicate that the results could be made public in the upcoming weeks.
However, despite the hopeful news about the data from this second study phase of the Oxford vaccine, the authors do point out some limitations in their study, including that participants in the older age group had an average age of 73-74, and have had very few previous illnesses. Therefore, they may not be representative of the general - older - population; for instance, of those living in nursing homes, or those over 80.
Easier handling and storage
One of the big differences between the vaccine that Oxford makes and the other two which have been mentioned previously is the technology used. The first vaccine uses a classic approach, based on the injection of the weakened virus, or parts of the virus, which directly stimulates the production of antibodies, and - in this case - also of T cells. The Moderna and Pfizer prototypes, on the other hand, inject fragments of the genetic material of the coronavirus (messenger RNA) in order for human body cells to use these fragments to manufacture viral proteins, which would then fuel the generation of antibodies. It is important to mention that the preservation and manipulation of the Oxford prototype is also much simpler than, at least, Pfizer's, which requires preservation at low temperatures.
In the light of the results, Dr Maheshi Ramasamy, a researcher of the Oxford vaccine group and a consultant physician, quoted: "Older adults are a priority group for Covid-19 vaccination, as they are at a greater risk of serious disease, but we know that they tend to have poorer vaccine responses. We are pleased to see that our vaccine was not only well tolerated in older adults, but also stimulates immune responses similar to those seen in younger volunteers. The next step will be to see if this translates into protection against the disease itself".
While one could think that in comparison with the Pfizer-BioNTech and Moderna results, Oxford's may seem disappointing, they do confirm that the means to reach the end of the pandemic are getting closer.