FILE PHOTO: Vials with a sticker reading, "COVID-19 / Coronavirus vaccine / Injection only" and a medical syringe are seen in front of a displayed Pfizer logo in this illustration taken October 31, 2020. REUTERS/Dado Ruvic/File Photo
Pfizer is one of the drug companies to have produced a coronavirus vaccine it says is more than 90 per cent effective. Reuters

Expert: 20 million Americans will recieve Covid-19 vaccination by 2021