It is very, very, very much awaited by European governments.
But the AstraZeneca vaccine, which is already suffering delivery delays, could be accompanied by a very big disappointment for the 27. While the European Medicines Agency (EMA) decides this Friday on its authorization in the EU, the German Vaccination Commission has already advised against it for people over 65, because of "insufficient data available […] to assess the efficacy of the vaccine" on this age group.
The British laboratory defends itself.
Vaccine strategies at stake
The stakes are high: the elderly are on the front line of vaccination campaigns in many countries… which rely on this vaccine.
Brussels, for example, has pre-ordered up to 400 million doses of the AstraZeneca / Oxford vaccine.
These doubts do not really surprise the specialists "It is likely that a weak vaccine response will be obtained (in the over 75s) and that it will be necessary to cover by protective barrier measures", wrote last July the Vaccine committee Covid-19 in a public notice to the French government.
"The flu vaccine works much less well in the elderly than in young adults," also recalls Claude Leclerc, honorary doctor at the Pasteur Institute.
This is a very clear problem and one of the reasons why Sanofi stopped its vaccine ”.
An immune system that declines with age
But why is it so difficult to reach this priority target?
“From a certain age, even before 65, our immune system begins to decline.
We put a lot of information in memory.
As soon as our immune system has encountered a lot of antigens, the possibility of stimulating lymphocytes is limited ”, underlines Claude Leclerc.
“The other thing that we see, but which should be taken with care, is that the microbiota of the elderly tends to become less diverse.
However, there is a very important link between the immune system and the microbiota ”, also suggests the specialist.
But be careful, because if these scientific observations are consensus, the "number of people of 65 years who were in the test was not very high", notes Claude Leclerc.
According to LCI, only 4,155 people over the age of 56 participated in the research, including only 1,460 over the age of 70.
"We will have to see what will come out on tests on very large scales," said Claude Leclerc.
"We must give preference to the messenger RNA vaccine"
“There is a decrease in immunity.
But it's heterogeneous, meaning that some people respond very well.
It should not be said that the elderly do not generally respond to the vaccine, ”underlines Renato Monteiro, head of the immunology department at Bichat hospital in Paris and president of the French Society of Immunology.
In the meantime, only the messenger RNA vaccine seems to be effective in the elderly.
“Messenger RNA has been shown to be more effective in the elderly because it produces the protein that will block the entry of the virus.
This is why we must insist on the importance of vaccination and give preference to the RNA vaccine, ”80% effective on seniors, according to the professor.
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Problem, there is a lack of doses today, reminds Renato Monteiro, who pleads for the development of preventive treatment based on neutralizing antibodies for positive patients who are elderly or have comorbidities.
Germany has already taken the initiative and ordered 200,000 doses of this treatment, used by Donald Trump during his Covid-19 infection.
