U.S. administers 270.8 mln doses of COVID-19 vaccines - CDC ReutersA look at COVID-19 vaccinations in Canada on May 16, 2021 Lethbridge News NowVietnam to get 31 Million Pfizer-BioNTech vaccine doses in 2021 as local cases keep rising The Star OnlineCDC Finds Covid Vaccines Highly Effective In Real Life — Even After Just One Dose ForbesPfizer vaccine side effects: Top-up dose causes more symptoms – eight symptoms to know?