A Covid-19 vaccination booster programme could begin for 32 million Britons as soon as September, officials have said.

New interim guidance from experts advising the Government sets out the priority list for who should get a third jab if a booster programme is needed.

The plans have been drawn up to ensure the NHS is prepared for any possible booster jab campaign while officials await more data on whether a third vaccine is required to bolster protection over the winter months.

It will coincide with the rollout of flu jabs, which health officials have said will be vital this winter as they prepare for a potentially difficult influenza season.

The UK is the first country in the world to publish interim guidance on a Covid-19 vaccine booster campaign, though a number of other countries are considering proposals.

The Joint Committee on Vaccination and Immunisation (JCVI) interim guidance sets out two stages for the Covid-19 booster programme:

– The first stage will see 15 million of the most vulnerable people across the UK offered a booster including over-70s, health and care workers, older care home residents, the clinically extremely vulnerable (those who were asked to shield previously), and people who are immunocompromised.

– The second stage will extend to a further 17 million people including over-50s, adults over the age of 16 who usually are offered a free NHS flu jab, those aged 16-49 in a Covid at-risk group, and people who are in regular contact with someone who is immunocompromised.

Officials have stressed that a third vaccine may not be needed but scientific advisers to the Government have said they are “taking no chances” and want to give the health service as much time as possible to plan.

Professor Wei Shen Lim, Covid-19 chairman for the committee, said: “The JCVI’s interim advice is that, should a booster programme be required, a third Covid-19 vaccine dose should be offered to the most vulnerable first, starting from September 2021 to maximise individual protection and safeguard the NHS ahead of winter.

“Almost all these people would also be eligible for the annual flu vaccine and are strongly advised to have the flu vaccine.

“We will continue to review emerging scientific data over the next few months, including data relating to the duration of immunity from the current vaccines. Our final advice on booster vaccination may change substantially.”

Health Secretary Sajid Javid said: “We welcome this interim advice, which will help us ensure we are ready in our preparations for autumn. We look forward to receiving the committee’s final advice in due course.

“Our first Covid-19 vaccination programme is restoring freedom in this country, and our booster programme will protect this freedom.

“We are working with the NHS to make sure we can rapidly deliver this programme to maintain protection for people in the winter months.”

People will be offered a single jab as a booster, so the rollout will be logistically easier for the NHS.

It is not yet known whether people will be offered the same vaccine, or a different one, but advisers said “all possibilities are on the table”.

Officials will know more when they get results from the CovBoost trial, which is expected to report back in August.

Experts previously said it was too early to say whether other people not listed in Stage 1 or Stage 2 will need a Covid-19 vaccine booster this winter.

Professor Jonathan Van-Tam, deputy chief medical officer for England, said: “We want to be on the front foot for Covid-19 booster vaccination to keep the probability of loss of vaccine protection due to waning immunity or variants as low as possible. Especially over the coming autumn and winter.

“The announcement of interim advice from JCVI is good news. It shows that the vaccine experts are thinking carefully about how best to use vaccination to protect the most vulnerable and ensure everyone’s lives can remain as normal as possible for the autumn and winter.

“Of course, we have to be driven by data, and there will be more data from vaccine booster studies for JCVI to look at over summer, so we should all remember that this advice is interim and might change between now and September; however JCVI has clearly set out the broad direction of travel which I agree with, and which ministers have accepted.”

The final JCVI guidance will be set out before September.