People in Scotland who were due to receive their second dose of the Covid-19 vaccine from next week have been told their appointments will be pushed back by months.

Patients and health staff who had expected to be fully inoculated within a month are now facing delays of 12 weeks so that more people can receive their first jab.

The delay was confirmed on Friday by chief medical official Gregor Smith, who said patients will be protected after just one vaccine shot.

He said the change was made so that jabs can be prioritised for those who have not yet received their first dose.

The UK Government Joint Committee on Vaccination and Immunisation also announced on Friday that they want to prioritise "as many people as possible on the Phase 1 JCVI priority list."

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It comes despite guidance from vaccine manufacturer Pfizer, who says there is no data which demonstrates that protection after the first dose is sustained after 21 days.

A statement from Scotland's Chief Medical Officer Dr Gregor Smith reads: "Those services that will be operational from Monday 4 January 2021 onwards should to ensure that all second dose appointments are booked in the twelfth week post the first dose.

"I recognise that the requirement to re-schedule second appointments is operationally difficult in the short term and may be unpopular with patients booked in for a second dose in the immediate future.

"However, for every 1000 people boosted with a second dose of covid-19 vaccine in January (who will as a result gain marginally on protection), 1000 new people would be delayed in receiving what amounts to very substantial initial protection which is in most cases is likely to raise them from 0% protected to at least 70% protected in typically 14-21 days."

A statement from Pfizer said: "Data from the phase three study demonstrated that, although partial protection from the vaccine appears to begin as early as 12 days after the first dose, two doses of the vaccine are required to provide the maximum protection against the disease, a vaccine efficacy of 95 per cent."

"There are no data to demonstrate that protection after the first dose is sustained after 21 days."

On Friday, Dr Christine Tait-Burkard, of the University of Edinburgh, said it makes sense to vaccinate most of the population to try and cut the spread of the virus and to make the vaccine last longer.

She told BBC Breakfast: “Overall, it makes sense to get more of the population vaccinated but I understand that it will have caused some concern for the people who were already scheduled for the second dose of the vaccine and they will have to wait longer, but the protection is very good from a single dose.”

She believes the Pfizer vaccine will still be used for vulnerable people while the Oxford-AstraZeneca vaccine, where more doses are available, can be rolled out much faster.

She suggested the army could used in the vaccine rollout which needs to be done quickly as “the NHS being under so much strain from the rising caseloads of covid that this needs to be done with additional help”.