Perry Manor nursing home, in Worcester, said it was "saddened by the losses" in recent weeks, after managing to stay free of coronavirus until last month.
The facility, which has capacity for up to 82 people, said 33 members of staff had also been infected but none had become seriously ill.
In its most recent inspection, the Care Quality Commission rated the home outstanding overall - the highest possible grading.
The home's bosses said "many" colleagues had tested positive for Covid-19.
Care UK said it was working with Worcestershire public health officials to minimise risks of further infection.
More than half of the home's staff had now been vaccinated, as well as residents who were well and had not tested positive, the company said.
Care UK regional director Dave Ashbolt said he would like to send condolences to families and friends of those who had lost someone from the home in recent weeks.
He said many on the team had tested positive and been self-isolating, so colleagues had been working extra shifts.
The regional director said: "Not only have they provided top quality, loving care to residents but they have also worked tirelessly to reassure relatives where they can and keep them up to date.".
Dr Kathryn Cobain, Director of Public Health in Worcestershire, said agencies were providing support to the care home.
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