A RECORD number of patients contracted Covid in hospital during the latest virus wave, figures reveal.

The statistics from Public Health Scotland show that a total of 913 people who tested positive over 14 days in mid-March had probably or definitely been infected following their admission to hospital.

The figures suggest that around 30 per cent of ‘Covid admissions’ during this period were people who had been exposed to the virus while in hospital.

HeraldScotland: Source: Public Health Scotland Source: Public Health Scotland

Research has shown that using air cleaners such as Hepa filters and special types of UV lamps can dramatically cut airborne levels of the virus, but official guidance remains to improve ventilation in hospitals by opening windows where possible and monitoring carbon dioxide levels.

It came as Health Secretary Humza Yousaf said the indicators are “positive” that Scotland is exiting the current coronavirus wave, but cautioned that it is "not the last wave we are going to have to deal with”.

Mr Yousaf was speaking during a visit to University Hospital Ayr as he confirmed that NHS Ayrshire and Arran has purchased the Carrick Glen private hospital in Ayr for £1.8 million, with plans to turn it into a dedicated elective hub specialising in orthopaedic surgery.

He said: “I think there could be other waves, certainly that my public health experts tell me, that we’ll have to deal with in the course of this pandemic.”

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Facemasks are set to be downgraded from a legal requirement to guidance in Scotland from Easter Monday, with access to free lateral flow tests also set to be rationed mainly to clinically vulnerable patients, frontline NHS staff and care workers.

Confirming that the plan would go ahead, Nicola Sturgeon said there has been “steady progress” in recent weeks “back to a greater sense of normality and a more sustainable way of managing this virus”.

The number of people currently in hospital with the virus has fallen from a peak of around 2,400 to 2,110.

However, the latest PHS report on Hospital-Onset Covid shows that there were a record 464 probable and definite hospital-onset cases in the week ending March 13, and 449 in the week ending March 20.

It is the first time in the pandemic that combined probable and definite hospital-onset cases have exceeded 400 in a single week.

HeraldScotland: PHS data shows there were a total of 3,114 Covid positive admissions in the fortnight to March 22, against 913 probable/definite hospital-onset cases in 14 days to March 20 which would be counted as new 'admissions'PHS data shows there were a total of 3,114 Covid positive admissions in the fortnight to March 22, against 913 probable/definite hospital-onset cases in 14 days to March 20 which would be counted as new 'admissions'

A case is considered a ‘probable’ hospital onset if the first positive swab is collected eight to 14 days after admission, and 'definite' if it is collected more than 14 days after admission.

Over roughly the same period - March 9 to March 22 - there were a total of 3,114 Covid hospital admissions.

Patients who test positive while in hospital are counted among the new Covid admissions.

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The Hospital-Onset report also shows that an additional 1,375 patients during the two weeks to March 20 had tested positive between one and seven days after admission to hospital, suggesting they had been infected in the community prior to admission.

The current wave of Covid has been driven by the super transmissible BA.2 Omicron strain and has been blamed for putting severe strain on the NHS as all Covid patients - regardless of symptoms - have to be isolated.

There have been calls from clinicians and some scientists to do more to limit hospital spread of the virus by improving air quality.

HeraldScotland: Scottish Government ventilation guidance Scottish Government ventilation guidance

Research carried out last year at Addenbrooke’s Hospital in Cambridge found that when portable Hepa filter/UV steriliser devices were placed in a Covid surge wards and run continuously, the virus became undetectable in air samples.

A separate study in March, whose authors included experts from Ninewells hospital in Dundee and the universities of Dundee and St Andrews, also found that inexpensive far-UVC light lamps had a disinfectant effect equivalent to 184 air changes per hour.

Ventilation in hospitals is expected to be around six air changes per hour (or 20 in operating theatres, and 10 in rooms for some higher risk patients).

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The experiment installed the lamps in the ceiling of a chamber which was continuously sprayed with an aerosol mist of Staphlococcus aureus bacteria - a highly common pathogen.

Within five minutes of exposure to the far-UVC light - which is harmless to human cells - airborne microbe levels had been slashed by 98%.

Co-author Dr Kenneth Wood, a lecturer in physics at St Andrews University, said: “Our trials produced spectacular results, far exceeding what is possible with ventilation alone.

"In terms of preventing airborne disease transmission, far-UVC lights could make indoor places as safe as being outside on the golf course on a breezy day at St Andrews.”

A Scottish Government spokesman said all infection control measures "are kept under review in light of new and emerging evidence".

He added: “Hospitals are now operating at significantly higher bed occupancy and the number of definite or probable hospital onset cases increases with higher Covid-19 occupancy in hospitals.

"Stringent measures have been in place since the start of the pandemic in all healthcare settings to mitigate the spread of coronavirus."