Lombardy rejects the mix of anti Covid vaccines but then aligns itself, Campania rebels and asks for clear answers. What do the studies carried out so far say about a first dose with one vaccine and a second dose with another?
The opinion of the Cts who recommended the use of the vaccine AstraZeneca for the over-60s, by decreeing in practice the stop to the administration of the product to the youngest also for the recall, has created in some cases confusion in the regions, with Lombardy first saying no to vaccine mix and then retracted, and the Campania which announces that it does not intend to proceed with the vaccination combo and asks the government for references and clear communications.
The doubts of the Regions
The loudest voice in these hours is that of the Campania governor Vincenzo De Luca which underlines how i continue changes of direction on the AstraZeneca vaccine have I compromise trust and the availability of citizens towards the vaccination campaign. And he asks clarity by the State, with definitions of roles (organization and logistics to the extraordinary commissioner, scientific communications and guidelines to the Ministry of Health) and direct indications (“It simply says ‘It is allowed’ O ‘it is forbidden’ ”, De Luca blurts out).
And since, the governor’s note reads, they exist scientific concerns (according to some experts there is not enough data on the combination protocols between different vaccines), the Campania yes rebellious to the government e reject the vaccine mix, at least until clear answers arrive from the authorities. A similar position had taken over the weekend there Lombardy, except then retract after a few hours and align with the ministerial indications.
The reassurances of the Ministry of Health
The minister Roberto Speranza renewed the invitation to the Regions to align themselves with the directives that provide for the stop of AstraZeneca under the age of 60, proceeding with the vaccination mix – a protocol which, as also remembered by experts from the CTS and external has already been approved by the regulatory authorities of some countries such as Canada.
“Several international clinical studies have highlighted the ability of the heterologous to induce an adequate production of antibodies”, he reminded al Corriere della Sera the member of the Cts Fabio Ciciliano. “There is obviously a lot of attention in monitoring adverse reactions. Preliminarily, greater efficacy was recorded in the production of antibodies with heterologous doses inoculated with an interval of 9-12 weeks (AstraZeneca-Pfizer) compared to the homologous vaccination protocol “.
Change vaccine, safety
To study the combined strategy with first dose with one vaccine and second with another are various research groups around the world. An English studio, called Com-The, which Oxford University took part in, analyzed the tolerability of the new option involving 830 volunteers. The investigation did not reveal any noteworthy safety issues, while a possible increase in mild and moderate side effects, such as fever and headache. The study is not yet peer reviewed but it was presented in a letter on Lancet. The limitations relate to the fact that the survey is carried out on people aged 50 and over and in younger groups “The reactogenicity could be greater”. However, we remember – a reassuring fact – that even from a recent research (which we talked about here) published on Nature Medicine it emerges that with regard to the vaccine of Pfizer-BioNTech there is no evidence of any increase in haemorrhagic and thrombotic events, cerebral thrombosis and thrombocytopenia.
Even a studio i study spanish of the Carlos III Health Institute of Madrid (discussed in Nature and here in preprint), conducted on 663 volunteers, analyzed the safety and adverse reactions in vaccinated people (441 received the second dose with Pfizer, different from the first) . The effects were mostly mild (two thirds) e moderate (about one third), as stated in the preprint, with pain at the injection site, headache, fever, muscle aches. There were no serious adverse reactions, the authors write, and the reactogenicity profile is defined “manageable”In the conclusions of the work.
The effectiveness of the mix
Also in the same Spanish study, the preliminary results on efficacy they look very encouraging. Two-thirds of the volunteers who were given a first dose of the AstraZeneca vaccine then received a booster with Pfizer-BioNTech vaccine after at least 8 weeks. “After the second dose the participants started producing much higher antibody levels than before “, we read in Nature, “and these antibodies were able to recognize and deactivate Sars-Cov-2 in laboratory tests”. The researchers write in the text’s conclusions in preprint that this combination induced an immune response robust.
A study from the University of Ulm, still in preprint e only on 26 volunteers, indicate that the mix is protective, in this sample of people, as much as vaccination with a single product. While a research of the university hospital Charité of Berlin, carried out on 61 participants (here in preprint), even identifies a slight increase in the production of T lymphocytes, another element of our immunity (cellular). The data are still few, but put together they suggest that the choice can be choose, both in terms of efficacy and in terms of safety, in the face of some more light side effects.