Rio to allow pregnant women to mix AstraZeneca and Pfizer vaccines

AstraZeneca pregnant
Photo: Unai Huizi Photography/Shutterstock

Rio de Janeiro health officials have begun administering Pfizer vaccine booster shots to pregnant and postpartum women who took a first dose of the AstraZeneca immunizer.

The measure seeks to avoid immunization delays caused by vaccine shortages, which has been a persistent problem across Brazil. Moreover, the combination of the two immunizers is proven to be effective, according to a study carried out by the University of Oxford.  

Researchers found that while the Pfizer-AstraZeneca combination often results in a higher prevalence of mild-to-moderate side effects, it also produces an increased immune response when compared to each vaccine in isolation. In April, Brazil’s Secretary for Primary Care Raphael Parente advised Brazilian women to postpone their pregnancy plans “for one to two years” as a way to avoid pandemic-related risks.