Combining Pfizer-BioNTech and AstraZeneca in the vaccination campaign produces “a powerful immune response against the Sars-CoV-2 virus”. This is what the preliminary results of a Spanish study, conducted by the Carlos III Health Institute of Madrid, on 663 volunteers and published in Nature have shown. A trial conducted in the UK, to verify the strategy of mixing the two vaccines, had already given reassurance on safety and will soon provide further data on immune responses. The researchers hope that the vaccine ‘mix & match’ strategy “can simplify immunization efforts for countries facing fluctuating supplies of various vaccines,” the study points out.
In April, the ‘Combivacs’ study enrolled 663 people who had already received a first dose of the AstraZeneca vaccine. Two-thirds of the study participants randomly received a booster with Pfizer’s mRNA vaccine after 8 weeks. A control group of 232 people has not yet received the second dose. After the second dose, the participants began “producing much higher levels of antibodies than before, and these antibodies in laboratory tests were able to recognize and inactivate SARS-CoV-2. they received the recall did not register any changes in antibody levels. ”