Three individuals from two Championship clubs tested positive for coronavirus during the past week, the English Football League has confirmed.
It is not yet known which clubs, players or staff are affected.
In the Championship, 2,858 people were tested over the past week and those who gave positive results must self-isolate, in line with EFL guidelines.
There were no positive results from 297 conducted in League One and 271 in League Two.
The number of positive tests is down on last week's total of 12, with eight of those from the Championship.
The restart of the second-tier season went ahead as planned on Saturday, and the two-leg League Two play-offs have also been played, with Northampton and Exeter winning through to Wembley.
League One play-offs involving Portsmouth, Oxford United, Wycombe Wanderers and Fleetwood Town will take place on 3 and 6 July.