More than 25 million people in the UK have now received a first dose of a coronavirus vaccine, but the NHS has warned of a month-long “significant reduction” in weekly supply of the jabs.
It comes as the European Medicines Agency (EMA) is expected to meet on Thursday to discuss the AstraZeneca vaccine, after a dozen European countries suspended rollout of the jab over isolated cases of blood clotting.
A letter to local health leaders in England asked vaccination centres and community pharmacy-led services to close unfilled bookings and “ensure no further appointments are uploaded” to booking systems in April.
NHS bosses said that as a result of the supply issues, people under the age of 50 should only get the jab if they are in a priority group, meaning younger adults could face a longer wait to be be vaccinated.
Dr Simon Clarke associate professor in Cellular Microbiology at the University of Reading, said while it was not yet known why the delay had occurred, the “ripple effects could last for months”.
“It will undoubtedly make the meeting of the target dates for lifting restrictions more difficult than they otherwise would have been,” he said.
“By pushing back the under-50s first doses, their second doses are also being pushed back.
“If full vaccination becomes required for holidays abroad or even more mundane things like going to the cinema, millions of younger people may end up being excluded from participating for the whole summer.”
Health Secretary Matt Hancock told a Downing Street press conference that vaccine supply was “always lumpy” and insisted the nation was on track to meet the target of offering a first dose to all over-50s by April 15.
But Labour’s shadow health secretary Jonathan Ashworth urged Mr Hancock to explain what these supply issues were and how the Government was aiming to resolve them.
“Trying to dismiss or downplay the legitimate concerns of anxious people waiting for a vaccine is simply not good enough,” Mr Ashworth added.
The Government’s Vaccine Taskforce “currently predict this will continue for a four-week period, as a result of reductions in national inbound vaccines supply”, the letter said.
A Pfizer spokeswoman said deliveries “remain on track” for the first quarter of its 40 million dose agreement with the UK, with a “steady supply of vaccines” delivered to the nation.
Meanwhile, an AstraZeneca spokeswoman said: “Our UK domestic supply chain is not experiencing any disruption and there is no impact on our delivery schedule.”
Asked about the letter, Mr Hancock said: “Supply is always lumpy and we are on course to deliver the offer that everybody who is aged 50 and above will be able to get vaccinated by the 15th of April. I recommit to that today.
“And, of course, these supply schedules have moved up and down throughout this whole rollout. It’s absolutely par for the course and that’s a normal operation letter.
“We are committed to all adults being able to get the jab by the end of July and we are on track to deliver on that commitment.”
Elsewhere, the UK faces a possible block on doses from the European Union after Ursula von der Leyen warned the bloc “will reflect on whether exports to countries who have higher vaccination rates than us are still proportionate”.
The European Commission chief said she wanted “reciprocity and proportionality” in exports, pointing out that 10 million doses of vaccine had gone from the EU to the UK.
Mr Hancock said the supply of vaccines to the UK from EU production facilities was “fulfilling contractual responsibilities and we fully expect those contracts to be delivered on”.