A leading Scottish respiratory doctor has said he is yet to see any "compelling evidence" for giving Covid boosters to healthy people.

Professor James Chalmers, who has treated hundreds of the sickest patients, said third vaccines should be reserved for the most vulnerable who had not achieved the same high levels of protection.

The Joint Committee on Vaccination and Immunisation (JCVI) is meeting today to consider the interim results from a study looking at the impact of different vaccines on top of two doses of Pfizer or AstraZeneca.

The head of AstraZeneca - Pascal Soriot- has said the UK government should wait to see whether two doses provide “continued, protective immunity”.

The JCVI has approved the use of a third vaccination for half a million people with severely weakened immune systems.

Meanwhile, Nicola Sturgeon is expected to announce in days if children aged 12 and over will receive vaccines.

Prof Chalmers said providing additional doses to healthy people also posed ethical questions, when so many people in poorer, overseas countries were yet to receive a first dose.

"I've yet to be shown really compelling data that says that we need to have boosters for the majority of people who have a normal immune response to the two doses," said Prof Chalmers, who is British Lung Foundation Chair of Respiratory Research at Dundee University's School of Medicine.

"I can totally see the rationale for those with immune problems but for people like me who are middle aged and low risk, the data shows two doses provide excellent protection.

READ MORE: Nicola Sturgeon says decision on vaccinating children expected 'within days' 

"I do worry that there are still very vulnerable healthcare workers and the elderly in many other countries who haven't even had a single dose."

The academic and clinician, who has just been presented with one of the most prestigious awards in his field, said the NHS was in for a tough winter with a significant flu outbreak but predicts flu vaccine uptake will hit record levels because, "we have won the argument with Covid vaccines."

"I'm getting very very nervous. The case numbers are high and hospitalisation have been creeping up. Glasgow colleagues are seeing a lot more patients in the past couple of weeks and we are getting busier in Dundee.

"I would love to say everything is going to be fine but I have to be quite honest and say I'm really quite worried. I think the health service is in for a very difficult winter.

"There is a spike in flu detections in India so it usually starts in the east and we see it coming. I think we are going to see a significant number of flu cases in the winter."

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He said the high Covid case numbers currently being seen in Scotland would likely hit England soon because of increasing numbers returning to the office and schools re-opening and said employers should be mindful of the vulnerabilities of workers.

He said: "The most important factor is the Delta variant and how transmissible it is and large groups of people coming together. England is likely to see a big rise in cases.

"There is still a risk and everyone's perception of that risk is different so I would be very cautious about saying that everyone should go back to the office. If you are someone who is young fit and healthy but you live with someone who is clinically vulnerable...you may be incredibly nervous."

READ MORE: Covid Scotland: NHS Ayrshire and Arran halts elective surgery 

Most of his research to date has focused on the chronic conditions COPD and bronchiectasis but over the past year he has become recognised as one of the country’s leading commentators on Covid-19.

As well as carrying out trials of new drugs to potentially treat the virus, the 41-year-old, who grew up in Killearn but now lives in Perth, also led the development of treatment guidelines for patients hospitalised with Covid-19. 

He was also among the first specialists in the UK to recognise that patients were experiencing long term complications of Covid-19 and initiated a Scotland-wide collaboration in April 2020 to research this topic. 

However, his research was put on hold to work in intensive care wards at Ninewells during the first and second waves of the pandemic.

"Right at the beginning I was talking to a good friend in Milan which was one of the worst hit Italian cities and he was telling me  stories about having to decide which patients get the last ventilator and crying on the phone. That was really terrifying.

"Thankfully we weren't having to make those kind of nightmare decisions.

"Last year, I thought we might get to a point where we could suppress it because the vaccines were so effective but the Delta variant changed the game because it's so much more transmissible.

READ MORE: Almost 1000 people in hospital as 5800 new Covid cases confirmed 

"We are the stage now where it's an endemic infection. It will with us for the rest of my life and your readers lives."

He contracted the virus in November and said of the experience: "it was pretty unpleasant, I recommend avoiding it.

"The saddest thing is seeing very sick patients who haven't been vaccinated."

He was presented with the European Respiratory Society’s Cournand Lecture Award yesterday “In recognition of his extraordinary contribution to respiratory medicine as a young investigator”. 

The award is named after a Nobel laureate, is only awarded every three years and is among the most prestigious awards in respiratory medicine.

It completes a hattrick of honours this year after being given the Peer Recognition Award from the American Thoracic Society and Outstanding Contribution from a Staff Member prize at the Herald’s Higher Education Awards.

He described the awards as an "unexpected honour."

"The past 18 months have been incredibly difficult for everyone, but I feel very lucky that, as lung disease clinicians and researchers, my colleagues and I have been able to make a difference. 

“It is incredible to look back on what has been achieved."