People in their 40s are likely to have to wait until May to get their Covid-19 vaccine after problems with a shipment of the AstraZeneca jab from India impacted supply.

Professor Martin Marshall, chairman of the Royal College of GPs, said news of constraints in supply was “disappointing” and “a bit of a setback”, and the focus in April in England will be on giving second doses to people who were vaccinated earlier in the year.

“The impact of this shortage of supplies will happen on the group that we were hoping to start on in April, which is the people under the age of 50 without any pre-existing conditions, who are now going to have to wait until May,” he told BBC Radio 4’s Today programme.

The news comes the day after the 100,000th jab was given at the York Vaccination Centre.

Cabinet minister Robert Jenrick also conceded that the rollout of vaccines would be slower than expected because of the shortage, while Professor Adam Finn, a member of the Joint Committee on Vaccination and Immunisation (JCVI), said vaccination of those aged under 50 “may kick off slightly later than we’d optimistically hoped”.

A delay in the delivery of five million doses of the AstraZeneca coronavirus vaccine from India is partly to blame for a forthcoming reduction in the UK’s supply.

The delivery had been expected from the Serum Institute of India but has been held up by four weeks.

The Housing Secretary told BBC Breakfast the final goal of vaccinating all adults with one dose by the end of July was still on track.

However, vaccination and rollout figures suggest the NHS had been set to easily beat that target.

Mr Jenrick said: “We are experiencing some supply issues so it does mean the vaccine rollout will be slightly slower than we may have hoped, but not slower than the target we set ourselves.

“We’re going to move forward as quickly as we possibly can but it won’t be as fast as we might have hoped for a few weeks, but then we have every reason to believe that supply will increase in the months of May, June and July.”

He said the Government had learned of coronavirus vaccine supply issues “in the last few days”, and suggested the problem is not due to reductions from a single nation.

“We have learned from some of our manufacturers that there are going to be some supply issues in the last few days,” he told BBC Radio 4’s Today programme.

“A number of global manufacturers are experiencing issues.”

Pressed if the issue was vaccine coming from India, he said: “It’s not that there’s any one factory responsible for this or any one country.”