There are new data to support heterologous vaccination


The new results coming from the Com-Cov study show that the AstraZeneca combination followed by Pfizer-BioNTech induces greater antibody and cellular responses than homologous vaccination with AstraZeneca

(Photo: Mika Baumeister on Unsplash)

It is an encouraging and partly reassuring result what it comes from Oxford, on the new results of the experimentation Com-The onefficacy of vaccine mixes, at least from the immune point of view. A bit more evidence, albeit still limited, in favor of the recent choice in Italy to propose, on an optional basis, the heterologous vaccination with mRna vaccine under 60 who have received a first dose with the vaccine of AstraZeneca. In fact, the Com-Cov results show that the immune responses triggered by the mix AstraZeneca (ChAd) e Pfizer-BioNTech (Bnt) are high, with some differences in the order of administration. The details on the pages of the pre-print of Lancet.

In recent weeks the results on the reactogenicity of the vaccine mix (tested in over 50s). They spoke of a greater risk of mild and moderate side effects for heterologous vaccination, but without any particular safety signals being reported. he had explained Mattew Snape of Oxford University, leading the firm. Today from the same trial also the results on the effectiveness of the immune response measured on 463 participants under study, who received vaccine doses 28 days apart.

In detail, they let you know from Oxford, the best cellular and antibody response is observed when one dose of the vaccine Pfizer-BioNTech follows that AstraZeneca, but that even in the opposite order the antibody response is greater than that observed with two doses of AstraZeneca. Compared to homologous vaccination with Pfizer-BioNTech – the one with the greatest antibody response observed in the study – the Pfizer-BioNTech mix followed by AstraZeneca induces a lower antibody response. The cellular response – measured for T cells – was greatest for the AstraZeneca and then Pfizer-BioNTech combination (followed by the Bnt / ChAd, Bnt / Bnt and ChAd / ChAd combinations). Overall, the results say one thing: the vaccination mix seems to be a viable and viable option with a view to making vaccination campaigns more flexible. Both looking at possible shortcomings in supplies, explain the authors, both in the face of new choices and vaccination strategies (just think of the Italian case).

“These results are an invaluable guide to the use of mixed vaccination schedules, even though the four-week interval we have studied here is shorter than the commonly adopted 8-12 weeks for the vaccine. AstraZeneca – commented Snape We know that this longer interval gives a better immune response, and results for the 12-week interval will soon be available ”.


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