S.Korea says AstraZeneca, Pfizer COVID-19 vaccines 87% effective after first shot

Data by the Korea Disease Control and Prevention Agency (KDCA) showed the Pfizer vaccine, jointly developed by BioNTech , was 89.7% effective in preventing infection at least two weeks after a first dose was given, while the AstraZeneca shot was 86.0% effective. Its analysis is based on more than 3.5 million people in South Korea aged 60 and older for two months from Feb. 26 and included 521,133 people who received a first dose of either Pfizer or AstraZeneca shot.