Bruce Aylward told a WHO meeting that interim results from Pfizer Inc's late-stage vaccine trial were very positive. United States President-elect Joe Biden declared the development positive news after convening with a coronavirus task force.
The vaccine has been tested on 43,500 people in six countries without raising safety concerns, but not all of the scientific data has been released yet.
News of the potential vaccine comes as the United States becomes the first country in the world to surpass ten million coronavirus infections, as the third wave of COVID-19 surges.