Malaysia's Govt to rollout heterologous Pfizer booster shots dose to be given to Sinovac vaccine recipients beginning October 22, 2021; WHO warns against mixing and matching Covid vaccines (Revised)

https://youtu.be/4mUox4WUgKo   https://youtu.be/hHhnBCh3JVY   WHO warns against mixing and matching Covid vaccines   https://youtu.be...