![Region of Waterloo Public Health on Twitter: "Mixing vaccines is safe and effective. If you had Moderna/Pfizer, you can safely take either for your 2nd dose. If you had AstraZeneca, you can Region of Waterloo Public Health on Twitter: "Mixing vaccines is safe and effective. If you had Moderna/Pfizer, you can safely take either for your 2nd dose. If you had AstraZeneca, you can](https://pbs.twimg.com/media/E4g6FU3WEAY1psK.jpg:large)
Region of Waterloo Public Health on Twitter: "Mixing vaccines is safe and effective. If you had Moderna/Pfizer, you can safely take either for your 2nd dose. If you had AstraZeneca, you can
Thinking of mixing and matching COVID-19 vaccine booster shots? There doesn't seem to be much point - ABC News
![A mix-and-match approach to COVID-19 vaccines could provide logistical and immunological benefits | PBS NewsHour A mix-and-match approach to COVID-19 vaccines could provide logistical and immunological benefits | PBS NewsHour](https://d3i6fh83elv35t.cloudfront.net/static/2021/06/GettyImages-1232570041-768x522.jpg)
A mix-and-match approach to COVID-19 vaccines could provide logistical and immunological benefits | PBS NewsHour
![Coronavirus Updates: NIH says Moderna's booster most effective mix with Johnson and Johnson first dose - ABC7 New York Coronavirus Updates: NIH says Moderna's booster most effective mix with Johnson and Johnson first dose - ABC7 New York](https://cdn.abcotvs.com/dip/images/11124686_101421-wabc-mix-and-match-vax-img.jpg)