Covid: Is there a limit to how much worse variants can get? – BBC News

https://www.bbc.com/news/health-57431420

look at their R0 (pronounced R-naught). It’s the average number of people each infected person passes a virus on to if nobody were immune and nobody took extra precautions to avoid getting infected.
That number was around 2.5 when the pandemic started in Wuhan and could be as high as 8.0 for the Delta variant, according to disease modellers at Imperial.