The effects of Covid-19 vaccine supply constraints are being felt in Dorset, where the number of first jabs administered has dropped, figures show.

NHS England warned last month that supply issues would mean priority for the jabs would be given to those in the high-risk groups and for second doses.

Data from NHS England shows that shows that 3,005 first doses of the vaccine were administered in Dorset in the week to April 11 – 3,284 fewer than the week before and the lowest in the preceding five weeks.

Across England, 355,000 first doses of the Covid-19 vaccine were administered in the week to April 11 – the lowest number in five weeks and 47% fewer than the previous week.

But the number of people receiving a second dose of the jab increased by 608,000, to 2.1 million people. Numbers for second doses are not available locally.

A delay in deliveries from India and the need to retest a batch of 1.7 million doses is behind the issues with vaccine supply in April.

Local health leaders were told to focus efforts on the top priority groups in a letter signed by Dr Nikita Kanani, medical director for primary care for the NHS in England, and Emily Lawson, chief commercial officer.

It said: "Those aged 49 years or younger should not be offered vaccination unless they are eligible via a higher cohort because they are, for example, clinically vulnerable, unpaid carer or frontline health and care workers."

The Nuffield Trust said the slowdown, however, had not affected the ability to reach vaccine targets.

Helen Buckingham, director of strategy, said: "In March, the Government warned that the rate of vaccinations would slow down due to supply constraints and we’ve seen that happen in line with that warning.

“The programme has exceeded expectations thus far, and continues to do so, with well over half the adult population now having received a first dose, and all vulnerable groups offered an appointment.

"It is good to see that appointments for those aged over 45 have started earlier than anticipated, and that self-referrals for care workers will restart next week.

"The slow-down therefore has not affected the ability to meet stated targets and there are no indications that it will.

“However, we should not lose sight of the fact that vaccine uptake is lower among some groups.

"Both the NHS and the Government must continue to work hard to ensure that any concerns are addressed and the vaccines themselves are accessible to all."

A Department of Health and Social Care spokesman said: “Our vaccination programme continues to make phenomenal progress – with over 40 million vaccines administered so far across the UK.

"We have hit our target to offer a vaccine to everyone in phase one of the vaccination programme and we are on track to offer a jab to all adults by the end of July.”