Vietnam to mix doses of Pfizer, AstraZeneca COVID-19 vaccines
A Spanish study found the Pfizer-AstraZeneca combination was highly safe and effective, according to preliminary results.
A healthcare worker hands over doses of the Pfizer-BioNTech COVID-19 vaccine to a doctor at Messe Wien Congress Center, which has been set up as coronavirus disease vaccination centre, in Vienna, Austria February 7, 2021.(photo credit: REUTERS/LISI NIESNER/FILE PHOTO)
