THE number of people getting the first dose of their Covid-19 jab will be “constrained” as a result of a reduction in the supply available, health officials have warned.

NHS leaders said there will be a “significant reduction” in the weekly vaccine supply available from the week beginning March 29 with a letter to regional NHS bosses saying the reduction will continue for a “four-week period”.

Health Secretary Matt Hancock addressed the letter at a Downing Street press conference yesterday and said it was a “standard” technical letter.

“Vaccine supply is always lumpy and we regularly send out technical letters to the NHS to explain the ups and downs of the supply of the future weeks and what you are referring to is a standard one of those letters,” he said.

Mr Hancock said there would be a focus on vaccinating the most vulnerable before moving on to the over 40s and said the Government would do “everything necessary” to ensure supplies continue.

He added: “We’re on track to offer a first dose to everyone in priority groups 1-9 by April 15.

“While we deliver on that commitment, we also want to ensure that this offer reaches everyone in groups 1-9.

“At the same time as opening up offers of vaccinations to all those who are 50 or above, we are going to do whatever it takes to reach all those in the most vulnerable groups who haven’t come forward yet before we move onto the next cohort, which is people in their 40s.

“Before we forge ahead I want us to be confident we’ve done everything we can to protect those most in need of protection and we will do all we can and do everything necessary to deliver the supplies that are contractually committed to protecting people in this country.”

He said “we fully expect” vaccine contracts to be delivered on despite EU chief Ursula von der Leyen warning the EU could block exports yesterday.

Mr Hancock said: “The Oxford/AstraZeneca vaccine was produced from research funded by the UK Government, tens of millions of pounds. We set up the supply chain, not just here in the UK but we helped set up the supply chain in the EU.

“This vaccine is provided at cost to the whole world - and we legally signed a contract for delivery of the first 100 million doses for people here, for people in the UK.”

About 90 per cent of people over 70 now have antibodies after having a jab and Mr Hancock said this explained why the death rate was falling so fast.

He said: “After a single dose of either vaccine, protection against Covid-19 is around 60 per cent, that’s protection against getting it, protection against hospitalisation is around 80 per cent and protection against death is around 85 per cent,” he said.