It’s strange #Sask Re-Opening Roadmap is all based on first dose, when it’s the second dose that provides highest efficacy. #covid19sk
— Dale Zak (@dalezak) May 7, 2021
“Pfizer data published in December 2020, the Pfizer-BioNTech vaccine is roughly 52% effective after the first dose.”https://t.co/yVeQpV3kgD