“People are still thinking about seasons. What we all need to get our heads around is this is a new virus and…this one is behaving differently,” Margaret Harris told a virtual briefing in Geneva, urging vigilance in applying measures to slow transmission that is spreading via mass gatherings

Moderna could have tens of millions of doses ready when and if the vaccine is deemed safe and effective, Collins told reporters on a call.

Pfizer said that if the trial was successful, it could seek regulatory approval as soon as October and supply vaccines for 50 million patients, at two doses each, by the end of the year.