Newcastle United have returned two more positive Covid-19 tests over the weekend, taking the total number in the last week at the club to five.
Steve Bruce revealed on Friday that three employees at the club were self-isolating after they missed the 2-0 win at Crystal Palace.
Now two more individuals who have access to the training ground have joined the group who are isolating at home as the club try to keep the outbreak to a minimum.
The club are adjusting protocols as they prepare for their visit to Aston Villa on Friday night, live on Sky Sports.
The squad have had the weekend off and are due to return to training as scheduled on Monday.
"It has been a tough week," Bruce said on Friday, before he was asked about avoiding an increase in the outbreak. "We sincerely hope so. It is very difficult at the minute.
"It is a concern and difficult to manage. We are trying our utmost to make sure we try and stay as safe as we can.
"Of course my concern is not just the welfare of the players, which is vitally important, but my members of staff too. We will do our best but it is difficult at the moment."
Coronavirus tiers: Newcastle unable to welcome back fans
Newcastle are one of 10 clubs that fall in tier 3 of the government's new coronavirus restrictions, which come into effect on December 2 and will deny supporters the opportunity of attending matches at St James' Park.
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Bruce says the return of fans is a "step in the right direction" but questioned why larger stadiums are not able to host larger numbers of socially-distanced fans.
"I can understand 4,000 fans [returning] if there's an 8,000-seated stadium, but what I can't quite digest at the moment is why it's only 4,000 or 2,000 when we've got the capacity to comfortably put somewhere in the region of 15,000 to 20,000 people in," he said.
"It's a step in the right direction and a small gesture. For the smaller clubs, 4,000 or 2,000 is welcome relief because they live off that."