Is Mix Vaccines Safe? What the experts say

Mixing AstraZeneca-Pfizer Covid vaccines for the first and second doses would be safe. This is revealed by a study by the University of Oxford which conducted an experiment on 830 volunteers aged 50 and over, an extract of which was published in a letter sent to the Lancet. A hypothesis on which, however, the experts are divided. Bassetti: “Important for the third dose” “Knowing that, whatever vaccine I have done before, I can still go for another vaccine and nothing changes, indeed I have a good answer, I think it is important”, says Matteo Bassetti, director of the Clinic of Infectious Diseases of the San Martino hospital in Genoa, he comments to Adnkronos Salute. “I was very cautious about this – recalls Bassetti – In fact I said ‘I would not mix vaccines’, instead they mixed and I would say that they have shown that they can be mixed. It seems to me a good message – he underlines – not so much for today when in the end people take the same vaccine because it is part of a path, as much as for the future, that is basically for the third dose that we will do in November-December-January “. Menichetti: “Yes to flexibility” Virologist Francesco Menichetti along the same lines. “The anti-Covid vaccine with an adenoviral platform such as AstraZeneca or Johnson & Johnson can lose efficacy due to the antibodies that are produced against the adenovirus. So the hypothesis of booster vaccines with different platforms, with messenger RNA, may make sense . Also in this case we take note of the trials that are important, but they are preliminary “, says the head of infectious diseases at the hospital of Pisa at Adnkronos Salute. “In any case, these are effective vaccines capable of soliciting either the first response or the immunological memory, therefore – underlines Menichetti – in a secular way I would neither recommend nor advise against it”. But if anyone who took the first dose of AstraZeneca had reservations about the booster, “making it clear that the second dose is absolutely no more dangerous than the first and that if you haven’t had any problems it can be done safely, I believe that, with the same interval at 3 months, could also access an mRna vaccine. This however – he specifies – will depend on the availability of vaccines and the policies to be implemented. But – notes the virologist – General Figliuolo, although military, seems to me to be demonstrating great flexibility. And therefore – concludes Menichetti – if there were the possibility, I would not be scandalized nor would I feel like drawing the red card “. Minelli: “Many unknowns” Rejects the hypotheses of using a mix of anti Covid vaccines from immunologist Mauro Minelli. “The world of research is certainly strange. Now, in the course of work and considering the inevitable refrain of being still in a state of emergency, we try to mix, changing the type of vaccine to be the viral vector to the mRna one, thinking that at the limit there could be some ‘slight’ side effect more and, perhaps, a lost work shift the day after the administration. It would be better to think of this method as a last chance “, he says at Adnkronos Salute the person in charge for the South of the Italian Foundation for Personalized Medicine. “Nothing is known of the effectiveness that the same mixture could have on the variants, especially on the Indian one which, on the other hand, seem to be sufficiently neutralized by the products available today administered according to the current canonical provisions – he continues – Nothing is known about what it could happen in subjects under the age of 50, given that the experimentation was conducted on a very limited number of people over 50 “. Minelli, on the other hand, recalls an alternative that has not been talked about but which could help. “We continue to disregard the real case history offered by objective and objectivable data resulting from the use of the vaccine Vaxzevria (AstraZeneca) which in 2700 people in the United Kingdom was, albeit for an oversight, administered at half the dosage, functioning as much as even better than the full dose. The dosage reformulation of an already existing product which, possibly remodeled, could provide, together with higher safety margins correlated to the same immunizing capacity, an availability of doses capable of doubling, with the vaccine equipment available today. , the number of people to be immunoprotected in every part of the world “. “Of course, we would also need an experiment here – argues Minelli – But why, perhaps for the vaccine mix ‘viral vector-mRNA’, no special experimentation has been started and, moreover, from what appears, on samples of numerically rather skimpy volunteers? Would it be more logical to experiment on smaller doses of the same vaccine, rather than on full doses of two different vaccines? And how many volunteers would be ready and extremely available to test half a dose of the viral vector vaccine? “. “I really don’t think it is a trivial thing, or something for which it is not worth starting a new quick experiment. Request, among other things, from us (Foundation for Personalized Medicine) already forwarded to AIFA with a communication sent a few weeks ago to the director general of AIFA – Minelli recalls – And, on the other hand, that a discovery or a simple intuition capable of making adjustments and concrete improvements in itinere to previous inventions, may even arise from an error, I do not think at all is a novelty given that, to codify it, the British have even coined the term ‘serendipity’ to highlight the relevance of chance in scientific discoveries. But of all this – he concludes – in the scientific chronicles of these days there is still no trace! “.