The Government has said it is “confident” all over-50s will be able to get a new coronavirus vaccine targeted against the Omicron variant.
Britain became the first country to approve such a “bivalent” jab on Monday that directly targets Omicron and the original Covid-19 strain.
Starting within a month, 29 million people will start being invited for jabs as part of the autumn booster campaign to try to protect the overstretched NHS this winter.
Nine million doses of the Moderna-made vaccine are already available.
Health chiefs signed a deal last year for 29 million doses to be delivered before the end of 2022.
Vaccines minister Maggie Throup said: “Obviously we’re getting stocks in other new vaccines ... and we’re getting further stocks as we go through the next few weeks, but there are other vaccines coming online as well.
“So we are quite confident that we’ll be able to deliver the programme with a bivalent vaccine throughout the next few weeks.”
The Government would not confirm stock levels - citing commercial sensitivity.
But Professor Anthony Harnden, deputy chair of the Joint Committee on Vaccination and Immunisation (JCVI), said people eligible for a Covid-19 booster jab should not worry about what type of vaccine they will receive.
“The key point is that people need to get vaccinated rather than worrying too much about the type of vaccine that they’re receiving,” he told BBC Breakfast.
“These are all very good vaccines, which have proven efficacy against severe disease - that’s hospitalisation and death.
“The whole basis of the programme is to target those vulnerable people for a booster to keep their immunity topped up for protection against severe disease.
“So the message really is get vaccinated with your booster and don’t worry too much about the type of vaccine that you’re getting.
“But for simplicity’s sake, we’ll be trying to use one vaccine and we believe that this bivalent vaccine is potentially a very good vaccine and so we’ll be using that in the first instance.”
He said those eligible for the autumn booster programme “would not get second-rate vaccines”, adding: “They’re all very good vaccines.
“Both the Pfizer and Moderna original strain vaccines are available.
“There may well be other vaccines in the pipeline.”
Half the population is now being urged to have a top up vaccination to reduce the risk of illness over winter and ease pressure on the NHS.
All over-50s and younger people with chronic conditions will be offered a jab through GP surgeries and pharmacies if it has been at least three months since their last dose.
An updated Pfizer vaccine that works in a similar way is expected to win approval in the next few weeks, and 54 million doses were ordered last year.
Ms Throup tweeted: “We will have enough supply to offer everybody eligible new vaccines targeted at the Omicron variant.”
Why is this new vaccine different?
Moderna’s bivalent vaccine targets two strains - the original Wuhan virus that emerged in China and the now dominant Omicron variant.
Until now all vaccines in use against Covid were based on the original virus.
Lab analysis showed the new bivalent jab produced about 70% more antibodies. Real world patient data will now confirm how much more protection that confers.
Will all over-50s get it?
The Government will be hoping Moderna delivers all its contracted supplies to the UK by the autumn so that population protection is maximised in time for winter.
It is understood nine million doses of the Moderna-made vaccine are already available. Health chiefs signed a deal last year for 29 million doses to be delivered before the end of 2022.
Around 29 million adults are eligible for an autumn booster.
An updated Pfizer vaccine that works in a similar way could gain UK approval in the next few weeks.
The NHS is not guaranteeing that everyone will get the newer vaccines. The original Moderna and Pfizer jabs will be offered if vaccine centres run out of supplies of the new ones.
How will it be rolled out?
The first NHS invites will be given out within a month, starting with the oldest and most clinically vulnerable.
People over the age of five who are classed as most at risk from the virus will be eligible, as will their household contacts.
NHS frontline and care home staff and carers aged 16 or over will also be invited.
Will this help Britain’s flu vaccine rollout?
Many patients will be encouraged to have their flu jab at the same time as their autumn Covid-19 booster jab, if supplies of both are available at the same time.
NHS chiefs are worried because this winter could be the first time the UK sees the real effects of both Covid and flu circulating.
