Ten members of staff and nine players have come down with the virus.
Seven of the nine players featured at Bloomfield Road against the Seasiders on Wednesday night.
Despite the outbreak, manager Chris Wilder has been told by the
EFL they must find a way to get their New Year's Day game against Sheffield United on.
Boro have even been told they should recall players to make up the numbers.
"It's possibly been the most difficult 48 hours of my managerial career. That says a lot," Wilder told BBC Tees.
"The game is on. We've talked to the EFL, who have told us we need to do everything we can to get it on.
We have a number of players that are available and what they've wanted us to do is supplement that group with players out on loan. I can't get my head around that.
"I'll be making a call to (Nottingham Forest boss) Steve Cooper to see if we can have Djed Spence back to sit on the bench. And the same with Lewis Wing. And Rumarn Burrell. We have players travelling down on their own to Sheffield.
"We'll have to recall the likes of Stephen Walker, Lewis Wing.
"The blunt message we keep getting back from the EFL is 'you have an obligation to fulfil this fixture'.
"People have been cutting corners. We're not. This is genuine. I'm not that type of manager, this isn't that type of club.
"This is 100 per cent a Covid outbreak. We have one injury, and he could play for 30 minutes. Let's put the cards on the table. Will some clubs have bent the rules to dodge a fixture? In my opinion 100 per cent..
"I'm a man of integrity and honesty. I will play a game anywhere against anybody on a level playing field. We have been absolutely decimated from a player and staff point of view."
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