Mixing COVID-19 vaccines safe but effect on immunity not yet clear: U.K. study

News 1130: It’s not yet clear how it affects the immune system, but preliminary study results suggest mixing certain COVID-19 vaccines is safe, though it causes some more frequent symptoms. This comes as more provinces, B.C. being the latest, decide to stop using the AstraZeneca shot as a first dose, reserving supply for second doses. Researchers at Oxford University say there was an increase in short-term adverse reactions, with more frequent mild to moderate symptoms reported, after the Pfizer vaccine was followed four weeks later by AstraZeneca, or vice versa.