The United Kingdom, the country in Europe most affected by the pandemic, has made vaccination a national cause to get out of the health crisis, faced with a new more contagious variant that forced it to adopt a third confinement in early January .
The country, which has already vaccinated more than 10 million people, and is targeting 15 million people by mid-February, is launching a study to test the alternation of doses of different vaccines on the same patients.
The objective is to make the campaign more flexible by making maximum use of the available stock.
This test, which will cost the British government £ 7 million (nearly € 8 million), is worth launching, according to Colin Harwood, professor of molecular microbiology at Newcastle University.
He explains why.
What are the advantages of rotating several vaccines on the same patients?
COLIN HARWOOD.
To be clear, it is a question of first giving a first vaccine, type Pfizer, to someone, then a few weeks later to administer a booster, such as AstraZeneca, to this same person and not to mix the vaccines. between them.
This process already has an advantage from the point of view of supply.
Sometimes there are problems with vaccine production.
Some components may be missing, resulting in less than scheduled vaccine production.
This is what happened in Europe.
However, this poses a problem if a person who has already received their first injection cannot receive their booster.
If another vaccine can be given instead, it would be more flexible and secure supplies.
The other advantage is that the protein in each vaccine, the active ingredient, is slightly different.
This means that the patient's immune system will face the virus differently and the spectrum of responses will be greater.
It is likely to produce additional antibodies and therefore increase the effectiveness of immunity.
The study is supposed to involve 800 people.
The national health service, the NHS, is in the process of recruiting volunteers.
Do you think this is sufficient?
Yes, because this study is based on already existing knowledge.
They're going to recruit healthy people, aged 50 and over, who haven't already received the vaccine of course, which makes them a particularly interesting group to follow.
I imagine that if a clear benefit emerges, then this study will be extended to other people.
Morning essentials newsletter
A tour of the news to start the day
Subscribe to the newsletterAll newsletters
Is there a risk in combining another vaccine for the booster?
A priori not because we start with already existing vaccines and on which there has already been a lot of research.
But this is also what this study will be used for: to find out whether the mixture of vaccines is effective against the virus and if this causes adverse effects.
The idea of alternating between vaccines was put forward in December, but British health authorities spoke out against it and recommended using the same vaccine.
What has changed since?
I don't know why the authorities decided against it.
Basically, we did not think that mixing vaccines was justified and we imagined that production plants would be more efficient.
But since there were these supply problems, the authorities saw an opportunity.
This would ensure that anyone who received a first injection will receive their reminder.
The experiment will cost the government £ 7 million.
Could the cost issue have been a hindrance?
I would have answered differently twelve months ago!
But given the economic effects of the pandemic in the United Kingdom, this sum is relatively reasonable in proportion to the benefits that could be drawn from the experience.
Have vaccine alternations already been carried out for other diseases?
There have been experiences against Ebola, indeed, but not extensively and I am not aware of other cases where it has been necessary to mix the vaccines.
Today, it is urgent to do so to deal with the supply problem.
It's very interesting because it shows that pharmaceutical companies are able to put aside the competitive aspects and work together to respond to the crisis.
Don't you think that it would be better to stick to a more careful management of vaccination, as is the case in France?
Difficult to answer.
It should be remembered that current technologies are very modern.
We can quickly develop very precise vaccines, then modify them to cope with different developments, for example.
Each country has the right to decide the ideal time to start its vaccination, but I'm sure the agencies that authorized these vaccines did so with good reason.
In the UK, over 10 million people have received their first injections and there have been no problems.
No one knows yet how persistent the immunization is, but there will be a follow-up on a group of individuals to get an idea on the subject.