A box and a vial of AstraZeneca’s COVID-19 vaccine are seen in a general practice facility, as the spread of the coronavirus disease (COVID-19) continues, in Vienna, Austria May 18, 2021. REUTERS/Leonhard Foeger
MADRID (Reuters) – 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, the researchers said on Tuesday.
The so-called Combivacs study, run by Spain’s state-backed Carlos III Health Institute, found the immune response in people who received a Pfizer shot was between 30 and 40 times greater than in a control group who only had AstraZeneca dose.
Few serious side effects were reported among the 600 participants, the authors said.
Reporting by Nathan Allen, editing by Inti Landauro