PATIENTS who contract flu in addition to the coronavirus which causes Covid-19 are more than twice as likely to die, according to new research.

Scotland's interim deputy chief medical officer, Dr Nicola Steedman, said it was clear that catching both infections at once is "extremely serious".

Dr Steedman urged everyone who is eligible for free flu immunisation this year, including healthcare workers, to take up the vaccine.

"Getting Covid and flu together is likely to be extremely serious," said Dr Steedman.

"And of course, what we also know is that the people most likely to get one infection are also potentially the most vulnerable when it comes to the other infection.”

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The deputy CMO issued the appeal as she outlined the findings of two new research studies into the combined effects of the flu virus and SARS-CoV-2, the novel coronavirus originating from China.

The first, led by Professor Calum Semple at Liverpool University, was carried out between February and June this year, analysing outcomes among Covid patients admitted to hospital in Scotland, England and Wales.

The findings have not yet been published but Dr Steedman, appearing with First Minister Nicola Sturgeon at the daily Covid briefing, said that patients admitted with both infections "spent more than twice as long in hospital compared to those with Covid alone".

This was true even when the data was adjusted for differences in patients' age, gender, and other underlying conditions.

In a separate study by Public Health England, 20,000 patients admitted to hospital between January and April - the end of the flu season - were tested for both Covid and flu.

From this sample, 58 patients were found to have both infections.

"The odds of dying were more than twice as high as those who had Covid alone, and almost six times higher than those who had neither infection," said Dr Steedman.

It comes as Scotland prepares to roll out its annual NHS winter flu vaccination programme.

Over-65s, those with underlying conditions, pregnant women, children aged two to five and Primary school pupils, young carers, and healthcare staff are eligible, but the programme is also being expanded this year to frontline social care workers, household members of those in the Covid shielding category, people aged 55 to 64s, and - if global supplies allow - to 50-54-year-olds.

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In the Southern Hemisphere - where winter is now coming to an end - many countries, including South Africa and Australia, have recorded unusually few flu cases.

It is thought that increased handwashing, hygiene, reduced social contact, facemasks and other interventions aimed at curbing the spread of coronavirus have also reduced transmission of flu.

Around 7000 people a year in the UK die from flu, rising to around 20,000 in a bad flu season, with cases typically taking off in November before peaking in January, February and March, with almost none in summer.

Professor Jurgen Haas, head of infection medicine at Edinburgh University, said: “We would expect a lower number of respiratory infections because of the hygiene measures, social distancing and so on, which is obviously a good thing."