No talk of injuries or players being in Africa in thisThere is no set, published criteria..... That's the problem.
Case by case basis blah.....
Whatever went on in that EPL meeting with the clubs a few weeks ago served to muddy the rules and leave the back door open fore injuries etc However, even before then there was no threshold for covid cases being declared not instances being quantifies other than 'bad outbreak'.
A guide to Premier League match postponements due to COVID-19
More details on the process by which recent fixtures have had to be called off
www.premierleague.com
If you take out their 1 Covid case their reasoning for postponing the match is due to injuries , suspensions or players bring at the Africa cup . I doubt that’s happened before