Burnley defender Ben Mee has tested positive for Covid-19 and will miss Saturday's Premier League game at Manchester City.
Clarets manager Sean Dyche said the 32-year-old was "fine" but that it is not clear when Mee will be available again.
Dyche, who said the club captain's case is an isolated one, would not reveal what percentage of his side has been vaccinated against coronavirus.
"Everyone's at liberty to decide what they wish to decide," Dyche said.
"I'm double vaccinated and all of my staff, as far as I know, are. I've got my children double vaccinated, my family double vaccinated.
"I'd recommend it but that's a personal choice. I can't force anything on anyone else."
Earlier in October, it was revealed that fewer than half of players at most Premier League and English Football League clubs were vaccinated.
There have been concerns about the rate at which players have been jabbed, which has prompted the Premier League to consider whether to "reward" clubs whose coronavirus vaccination rates are high.