LONDON (Reuters) - Britain will see a significant reduction in the amount of COVID-19 vaccines available from March 29 due to a cut in manufacturing supply, it said on Wednesday, in a setback to one of the fastest rollouts in the world.
Britain is on track to have given a first COVID-19 shot to half of all adults in the next few days and passed 25 million first shots on Wednesday.
Health Secretary Matt Hancock said supply often fluctuated but the country remained on track to have given vaccines to priority groups by April 15 and all adults by the end of July.
"Vaccine supply is always lumpy and we regularly send out technical letters to the NHS to explain the ups and downs of the supply over the future weeks, and what you're referring to is a standard one of those letters," Hancock told reporters.
A letter sent around to the state-run health service said there would be a "significant reduction in weekly supply available from manufacturers beginning in week commencing 29 March, meaning volumes for first doses will be significantly constrained".
"They now currently predict this will continue for a four-week period, as a result of reductions in national inbound vaccines supply."
Hancock did not say why there would be such a reduction.
Brussels threatened on Wednesday to ban exports of COVID-19 vaccines to Britain to safeguard scarce doses for its own citizens as it aired frustration over a lack of deliveries moving from AstraZeneca in Britain to Europe.
The political editor of the BBC reported however that the reduction was linked to fewer vaccines being available from AstraZeneca than expected.
The letter said for the four-week period it would focus on making sure all those in the most vulnerable categories had received their first shot, and giving second vaccines to those who have already received their first.
(Reporting by Michael Holden and Alistair Smout; Editing by Kate Holton)