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Before a viral vector vaccine, that is, with a carrier virus that carries Sars-CoV-2 antigens to stimulate the immune response. Then an m-RNA vaccine, which provides instructions for the development of specific antibodies against the virus responsible for Covid-19.
This is what the new indication for vaccination proposes for people under the age of 60. After a first dose of AstraZeneca, therefore, a second dose with another vaccine is scheduled. There are currently only a few studies, but several researches are coming up on this “combination”.
Because you can trust
To try to understand, without obviously giving definitive answers that can only come from clinical evidence, let’s see the situation. This strategy of “mixing” two vaccines with different mechanisms of action is based on a choice already made in some countries, such as Germany and the United Kingdom itself. And as far as is known so far no problems have emerged particular, even if not many scientific papers have been published, also because in practice the goal is always the same: to ensure that the organism, and more precisely the immune system, receives the “indications” useful for preparing specific antibodies in comparisons of the virus.
So, in case of infection, thanks to vaccination you can have a response. A single dose, regardless of the type of vaccine, can already offer a first reaction by the immune system, but it is with the second that the vaccination cycle ends, pending a possible further “booster” that will be decided in time and in the ways.
With two vaccines with different mechanisms of action, therefore, the strategy does not change, which must lead to obtaining an efficient immune coverage so as to avoid the risk of developing Covid-19 in a serious form and therefore prevent the risk of hospitalizations or deaths, particularly in frail people by age or pathology, linked to the disease.
Obviously, however, not all the scientific community agrees on this method of administration: there are those who argue that thanks to the stimulus offered by vaccines, even with a different mechanism of action, a similar or even better result can be obtained in any case. terms of defenses that develop.
But there are also those who underline that there is not yet enough data to go ahead on this path and therefore recommend keeping the same vaccine for the booster too. In this sense, the position of the experts of the PTS (Transversal Pact for Science) should be emphasized, who recall how the debate on heterologous vaccination is underway but at the same time there are no definitive indications on the subject by the structures appointed to example the European Medicines Agency.
How to behave?
The doctor it is the point of reference to dispel any doubts for people who know they are undergoing a booster with a vaccine other than the first. However, the important thing is to ensure that the maximum number of people with double vaccination is preserved, since in this way it is possible to reduce the circulation of the virus and therefore also limit the risk of developing variants linked to the ability of the virus to “escape” what happens.
This is an important goal, also in light of the Delta or Indian variant, if you prefer, since it is important to limit the possibility for the virus to mutate and replicate. In this sense, it must be said that just recently a research has been published in the Lancet that demonstrates how with the two doses of vaccine (in this case of a single type) good protective coverage can be obtained even in the case of the Delta variant: even if you can be (and can rarely happen) infected, the symptoms are still mild.
