Madrid: A Spanish study on mixing Covid-19 vaccines has found that giving a dose of Pfizer ’s drug to people who already received a first shot of AstraZeneca vaccine is highly safe and effective, preliminary results showed on Tuesday. The Combivacs study , run by Spain’s state-backed Carlos III Health Institute, found the presence of IgG antibodies in the bloodstream was between 30 and 40 times higher in people who got the follow-up Pfizer shot than in a control group who only received one AstraZeneca dose. Meanwhile, the presence of neutralising antibodies rose sevenfold after a Pfizer dose, significantly more than the doubling effect observed after a second AstraZeneca shot.Around 670 volunteers between the ages of 18-59 who had already received a first dose of AstraZeneca’s vaccine participated in the study, with some 450 given a Pfizer dose. Just 1.7% of the participants reported severe side effects, which were limited to headaches, muscle pain and general malaise, said Dr Magdalena Campins, one of the study’s leaders. Spain embarked on the study to determine how best to proceed after limiting AstraZeneca's shot to people aged over 60 due to concerns about blood clotting in younger people.

Source: Economic Times May 19, 2021 00:56 UTC