Pfizer, Moderna COVID-19 vaccines highly effective after first shot, suggests study

COVID-19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc reduced the risk of infection by 80 per cent two weeks or more after the first of two shots, according to data from a real-world study of vaccinated US healthcare personnel and first responders released on Monday. The risk of infection fell 90 per cent by two weeks after the second shot, a study of just under 4,000 people found.COVID-19 vaccines developed by Pfizer Inc with BioNTech SE and Moderna Inc reduced the risk of infection by 80 per cent two weeks or more after the first of two shots, according to data from a real-world study of vaccinated US healthcare personnel and first responders released on Monday. The risk of infection fell 90 per cent by two weeks after the second shot, a study of just under 4,000 people found.