Around 89.4% of staff working in older age care homes had received two vaccine doses as of October 31, according to data from NHS England.
The remaining 49,040 staff - around one in 10 of the total - had not been recorded as having received two doses at this point.
The equivalent figure for staff in care homes for under-65s is 13.6% - 11,924 staff.
This suggests a total of 60,964 staff have not had a second jab or their second jab has not been reported as of the end of October.
The total includes staff who cannot be vaccinated for valid medical reasons and those whose vaccination status is unknown, while there may also be a time lag in some vaccinations being reported.
There is no published data on how many staff have self-certified as exempt or have applied for official proof.
But it is understood that this is around several thousand staff.
The Government has made it mandatory for staff in registered care homes in England to have both jabs as a condition of deployment, unless they are exempt for valid medical reasons.
From next Thursday, it will be a legal requirement for staff who are not exempt to be doubly vaccinated if they are to continue in their role.
The regulations also cover any worker, including NHS staff, tradespeople and inspectors, who needs to enter a care home as part of their employment.
But residents and their visitors, or people who need to enter the residence to provide emergency assistance or urgent maintenance, or under-18s will not need to show proof of vaccination.
Sector leaders fear an exodus of care staff which they warn will threaten safe care.
Adam Purnell, director of social care at the Institute of Health and Social Care Management, said it will be "horrific" for the sector to lose so many staff so suddenly, and that residents in some settings will be at risk.
He accused the Government of a "severe lack of listening and understanding" over the potential impacts of the policy, which care bodies have been warning of for months.
He told the PA news agency: "People are on the edge, I think business viability is a major concern moving forward.
"If we're talking about protecting the NHS throughout the winter, to protect the NHS we need a fully functioning social care service, which we're not going to have."
He said there would be "no shame" in the Government postponing next week's deadline until after winter, as this would reduce the burden on services.
He continued: "I worry that one of the after-effects of this is people won't be taking their annual leave, people won't be taking their downtime, and it's only going to increase over-exertion.
"We're going to see burnout across the sector."
Mike Padgham, chairman of the Independent Care Group, said the Government should "rethink" next week's deadline, adding that shortages could lead to homes closing and have a "knock on effect on the health service".
He said: "We're struggling now, Covid hasn't gone away, and we could do with a bit longer.
"But also, recognising the pressures of a difficult winter, if we're already that short of staff, it doesn't make sense to impose it when we might find that facilities that help the NHS aren't there to help in the community."
A Government consultation on extending the mandatory vaccination condition to wider social care and NHS staff has recently concluded.
The Government is expected to make an announcement imminently.
The figures show that almost a quarter (24.3%) of staff working in younger adult care homes and domiciliary care providers have not been reported as having had both jabs, a total of 116,871 staff.
Three quarters of staff working in other social care settings, including non-registered providers and those employed by local authorities, have had their first jab.
But only about a third were doubled jabbed as of October 31, with 383,760 staff in these settings not doubly vaccinated or reported as so at this point.
The Department of Health and Social Care said it is its responsibility to "do everything we can to protect vulnerable people".
A spokesman said: "We are working closely with local authorities and care home providers to ensure there will always be enough staff with the right skills to deliver high quality care."