NHS Providers urged the government to offer cash bonuses of around £500 each to stop staff leaving for Christmas jobs in hospitality, supermarkets or online firms such as Amazon.
Social care staff must now all be double-vaccinated to work in care homes, with those working in other settings having a deadline of April to get both jabs.
This has led to fears of a mass exodus in a sector that already has more than 100,000 vacancies.
NHS Providers chief executive Chris Hopson said: “Colleagues in the social care sector we’ve spoken to think the size of the bonus might need to be a minimum £500, so with 1.5 million social care staff that comes to a total of £750 million, which is a huge amount of money.
“It is this kind of immediate, emergency action that the government needs to be thinking about in the next fortnight because our system has to stop the current flow of people leaving social care going into other industries like retail, hospitality and logistics.
“We know those industries are trying to secure a Christmas workforce as the next six weeks is where they make a significant amount of their profit.
“That’s why Amazon and others are paying a substantial bonus.
If we don’t stop the loss of social care staff, that will be a real issue and it needs to be looked at really quickly.”
It comes as a report for NHS Providers, which represents NHS trusts in England, found the health service is facing unprecedented levels of pressure for this time of the year, which is impacted by issues in social care.
A poll of 172 board level trust leaders from 114 trusts found:
87% are extremely concerned about the impact of winter on their trust and local area. When asked the same question last year, the figure was 56%.
84% are very worried/worried about their trusts having the capacity to meet demand for services.
85% are very worried/worried that insufficient investment is being made in social care in their area, which has a knock-on effect of delaying discharges of people from hospital.
94% are extremely/moderately concerned about burnout among their staff.
Only half (51%) rate the current quality of healthcare provided by their local area as very high or high.
NHS Providers said the survey, which is carried out annually, shows a much higher level of concern about the coming winter months than ever before.
It warned that hospitals are struggling with an increased demand for emergency care, growing waiting lists, staff shortages and the prospect of high levels of Covid-19, flu and other respiratory viruses.
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Mr Hopson said the demand on ambulance services, which are all on their highest level of alert and are missing every response time target, was contributing to pressure alongside already-high levels of bed occupancy across the NHS.
He added: “The message from trust leaders is loud and clear: judging by the pressure the NHS is currently under, the service is heading for the most difficult winter in its history.
“The current Covid caseload is considerably lower than the peak at the start of the year, but when we consistently run our health and care system at the limit of its capacity, it doesn’t take much extra pressure to increase risk to patient safety and quality of care.”
Mr Hopson said around a third of beds in an average district hospital are taken up with Covid patients, have been taken out for infection control or are taken up with patients waiting for discharge.
He said cancelling planned operations over the winter was a “last resort” but said some hospitals may choose to do so.
“Staff are working extremely hard to minimise the risk of this happening and trusts want to do everything they can to avoid blanket cancellations,” he added.
NHS Providers deputy chief executive Saffron Cordery said: “We know that as pressures mount on the NHS, so do the risks in terms of the quality of care we can offer to our patients.
“We start to see handover delays, fewer available beds, longer trolley waits, increased waiting times and postponed treatments.
“Even when pressures on the NHS are at their peak, the health service doesn’t break or fall over."