The requirement for frontline workers in regulated health and care settings to be vaccinated against coronavirus could have “significant” implications for the workforce and delay care, according to a Government document.

Frontline staff will be required to have had both doses of a vaccine by April 1 next year as a condition of deployment, unless they are exempt, Health Secretary Sajid Javid announced on Tuesday.

An impact assessment from the Department of Health and Social Care says the number of workers who may leave as a result of the policy is uncertain, but suggests the impact on workforce levels could be “significant”.

Any reduction in staffing levels may lead to reduced or delayed health and social care services, the document warns.

And it says it is likely to have a greater impact in social care settings, where uptake rates are lower compared with healthcare settings.

Overall, the policy will apply to 1.813 million health staff and 503,000 staff in domiciliary and other social care settings, the impact document says.

It estimates that 123,000 staff – 88,000 health and 35,000 social care staff – will remain unvaccinated and therefore will not fulfil the conditions of deployment by the end of the 12-week grace period.

A further 3,000 social care staff are expected to leave the sector even in the absence of the policy based on high turnover.

Overall, the 126,000 staff unable to be deployed represents 5.4% of the total number to whom the policy applies.

Some 54,000 workers – 27,000 health and 27,000 social care staff – are expected to be vaccinated under the policy.

This is 2.3% of the total staff to whom the policy applies.

The Government estimates the cost of replacing unvaccinated workers at the end of the period will be £270 million – £185 million for healthcare workers and £86 million for social care staff.

Additional costs that cannot be monetised include potential disruption to services needing to replace unvaccinated staff, productivity losses, needing to familiarise providers with the regulations, and administrative costs.

It estimates the policy will generate £11.4 million in benefits, meaning the net cost is estimated to be £259 million.

Other benefits include greater confidence for patients and care users and the overall health, wellbeing and economic benefit to society that come with better control of the virus.

It says pressure would be put on NHS services, with the system currently stretched with a waiting list of 5.72 million and a high level of vacancies.

A larger proportion of health staff are expected to leave at the end of the grace period, reflecting what has been observed among care home staff, to whom the requirement already applies.

For social care, the number of staff who could leave “presents a significant workforce capacity risk”.

The document reads: “In the context of a sector which experiences a relatively high annual workforce turnover rate of over 34% (of which a third are sector exits), and where recruitment forms a regular part of their operations (our cost estimates account for those who would have left the sector anyway), this presents a significant workforce capacity risk.

“Moreover, this is in a sector that is already facing serious recruitment challenges owing to high competition for labour as the economy reopens, with competing sectors such as retail, logistics and hospitality offering higher wages and better conditions, as well as high levels of vacancies (now higher than pre-pandemic).”