Pfizer-BioNtech and AstraZeneca COVID-19 vaccines is safe, but it’s still too soon to tell whether combining doses will provide protection against the virus.The early results from a University of Oxford study found that mixing the two vaccines may increase the frequency of mild to moderate side effects.
But the symptoms, referred to in the study as “reactogenicity,” were short-lived — lasting no longer than a few days — and there were no hospitalizations or other safety concerns.“Whether or not this will relate to actually an improved immune response, we don’t know yet,” Dr.