Northern Ireland’s Covid-19 vaccine rollout is set to be delayed by several weeks due to changed advice on using AstraZeneca jabs, the head of the programme has said.

Patricia Donnelly outlined the consequences of the new advice from the Joint Committee on Vaccination and Immunisation (JCVI) that people under 40 should be offered an alternative to AstraZeneca due to a link to rare blood clots.

The clotting issue had already prompted the under-30 age cohort to be offered the Pfizer jab instead of AstraZeneca.

Ms Donnelly said the majority of people aged 30-39 will now be offered the Pfizer jab too, with these doses being primarily administered in regional vaccine centres away from the main centre at Belfast’s SSE Arena.

People who have already received a first dose of AstraZeneca will receive a second dose of the same jab, while others can make an informed choice to have the AstraZeneca vaccine if they wish.

Prior to the JCVI decision, Ms Donnelly told Stormont MLAs on Thursday that Northern Ireland was set to complete the vaccination of the adult population by the end of August.

She said the decision to offer the under-30 age cohort a vaccine other than AstraZeneca had pushed the timeline for delivering all first doses back to potentially the end of July.

Ms Donnelly said the latest advice from the JCVI would lead to a further slowing of the rollout.

“Protecting our adult population through vaccination is a huge and unprecedented undertaking,” said Ms Donnelly.

“Logistical challenges are inevitable, but the programme has already proved itself to be highly resilient.

“I would again appeal for patience from the public, as we reset the programme in light of the updated JCVI advice.

“Pfizer supplies remain steady but limited, so our progress with the 30-39 age group will be limited for the next few weeks.

“Likewise, those under 30 will have to wait a few weeks before being offered appointments for their first dose.”

A number of changes to Northern Ireland’s vaccine programme will come into effect from Monday May 10 as a consequence of the JCVI advice.

– People aged 40-plus can book AstraZeneca first-dose appointments at the SSE Arena vaccination centre and community pharmacies.

– People aged 30-39 can book their Pfizer first-dose appointments at the other regional health trust vaccination centres in Northern Ireland.

– People aged 30-39 can choose to make an informed decision to receive the AstraZeneca vaccine from participating community pharmacies if they prefer, or if they decide they would rather not wait to receive an alternative jab.

– Anyone aged under 40 already booked for their first vaccine at one of the trust centres, including the SSE Arena in Belfast, will have this appointment honoured – with the Pfizer vaccine.

– Anyone of any age who has received an AstraZeneca first dose should proceed with their second dose of AstraZeneca – unless they had an extreme adverse reaction to their first dose.

Northern Ireland’s chief medical officer Dr Michael McBride said: “It is important to reiterate that the potential risk associated with the AZ (AstraZeneca) first dose is extremely rare and that the threat from Covid-19 is much higher for the majority of adults.

“Getting vaccinated against this virus gives us hope – it protects us and helps us to start to reclaim normality.

“I am looking forward to getting my second dose of AstraZeneca in the near future and I would again encourage everyone to come forward without delay for their first and second jabs when it’s their turn.”

One further death of a patient who had previously tested positive for Covid-19 in Northern Ireland was announced on Friday along with 65 new cases of the virus.

On Friday morning, there were 62 Covid-19 positive inpatients in hospital, of whom six were in intensive care.