Zach Binney, an epidemiologist at Emory University in Atlanta, Georgia, said: “The thing that people need to understand, epidemiologically speaking, is that every person you add to a gathering adds risk.
“Five people is more dangerous than two, ten is more dangerous than five, 500 is more dangerous than ten, 60,000 is very, very dangerous.
“Even if you have really low community-based transmission, it only takes a few people in that crowd of 60,000 for there to be a risk of something very significant happening.
“As a scientist, I hate to say I am ever 100 per cent sure about anything but I am as close to 100 per cent as I’ve ever been that we cannot return to filled-to-capacity stadia until we have a vaccine. Period.
“The best guess is about 18 months, could be a little more, could be a little less.”
Football chiefs are desperate to complete the 2019/20 season by whatever means necessary.
Premier League players are understood to have been told to prepare to return to training with their respective clubs at the end of May.
The middle of June is reported to be the target for action to resume, behind closed doors.
Multiple games could be played at neutral venues on the same day – with Wembley and St George’s Park offered by the Football Association as a potential solution – in order to get the campaign finished.