Rome, June 14, 2021 – Covid vaccines, despite the doubts of some governors and experts, today theItalian drug agency (Aifa) announced that “atry mixed vaccination for people under 60 who have received a first dose of Vaxzevria (AstraZeneca)”.
The AIFA opinion reads: “On the basis of clinical studies published in recent weeks, the Technical Scientific Commission has decided, in the face of a significant enhancement of the antibody response and a good reactogenicity profile, to approve the vaccine mix (first dose with Vaxzevria and second dose with Comirnaty or, by analogy, with the Moderna vaccine) “. The implementation resolution is currently being published in the Official Journal.
Antibody response: clinical data
With the mix of vaccines, AstraZeneca for the first dose and Pfizer (or Moderna) for the second, there is a good antibody response, even if the mild side effects, underlines the Technical Scientific Commission of Aifa. “In addition to the biological plausibility that different methods of expression of the spike protein in the recipient cells are able to induce responses to largely overlapping epitopes – writes the Cts of Aifa – this approach is supported by the clinical data deriving from 2 studies clinical trials published in recent weeks conducted in Spain and England respectively and, which show good results in terms of antibody response (CombiVacS) and safety (in terms of acceptability of side effects) “.
Faced with a “significant enhancement of the antibody response obtained with the first dose, suggestive of a booster effect”, writes the CTS, “the vaccine mix (first dose with Vaxzevria and second dose with Comirnaty) presented a reactogenicity profile that , although characterized by a greater frequency in terms of local and systemic side effects of a mild / moderate degree, it appeared acceptable and manageable on the whole “.
When to give the booster
On the basis of these studies, the commission believes that “the available data may support the use of the Comirnaty vaccine and, by analogy, the Moderna vaccine, as a second dose to complete a mixed vaccination course, in subjects under the age of 60 who have already carried out a first dose of Vaxzevria vaccine “. Finally, on the basis of the CombiVacS study, it is believed “that the second mRNA vaccine administration can take place 8-12 weeks after the administration of Vaxzevria”.
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