Tag: University of Edinburgh study

NHS Lothian releases results of research into transmission of COVID-19 from hospitals into care homes

Scientists in NHS Lothian have helped to develop national infection controls after studying COVID-19 transmission between hospitals and care homes.

The teams found that 99 per cent of patients discharged from hospital into care homes during the first wave of the pandemic did not introduce COVID-19 into care homes.

The study, conducted with the University of Edinburgh, focused on patients in Lothian discharged from hospital into 130 care homes from 1st March 2020 to 31st May 2020. 

Of the 787 discharges in this time, the researchers found that the majority – a total of 776 – did not introduce COVID-19 into care homes as a result of their hospital stay.

Forty-one of the discharged patients had a positive COVID-19 test within two weeks of leaving hospital and genome sequencing was used to identify if these cases could be linked.

The study found that 30 patients likely contracted this in the care home or from the community.

The results of 10 patients were inconclusive and one patient was confirmed to have contracted COVID-19 during their stay in hospital.

Very sadly, this patient later passed away and a number of residents in their care home subsequently contracted COVID-19.

Dona Milne, Director of Public Health and Health Policy, NHS Lothian, said: “This study has shown that 99 per cent of hospital discharges didn’t introduce COVID-19 cases into Lothian care homes during the first wave of the pandemic.

“However, we’re able to say with certainty that one care home outbreak in this time originated from us. We are deeply saddened by this, and our heartfelt apologies and condolences are with the families and loved ones of those affected.

“We began testing symptomatic care home residents very early in the pandemic, so it’s been really important for us to use this information to find out what we can learn about how the virus was contracted and spread and how this linked to our hospitals.”

Before the nation went into its first lockdown when testing wasn’t widely available, NHS Lothian built capacity into its labs specifically to PCR test those who were symptomatic in hospitals and care homes.

Because of this early testing of symptomatic patients, in-depth data was available to the research team to enable them to genome sequence the transmission of the virus as part of the study.

Dr Kate Templeton, Head of Molecular Diagnostics for NHS Lothian who led the study, said: “Testing was a priority for us from the beginning and we were the first health board in Scotland to build capacity in our labs specifically for care home residents.

“This early testing has enabled us to genome sequence the virus and track where this was acquired and how this spread, leading to the creation of an outbreak methodology which has informed best practice at both Scotland and UK-level.

“This methodology not only has applications to COVID-19 but other viruses too and has been vital in learning lessons around infection control. It also clearly shows that the protection of the most vulnerable in society needs to involve not just health authorities but the community too.”

You can read the study in full here.

Face coverings can reduce Covid-19 transmission risk, University study says

Wearing a face mask or other covering over the mouth and nose reduces the forward distance travelled by an exhaled breath by more than 90 per cent, Edinburgh University research suggests.

Scientists testing the effectiveness of seven types of face covering – including medical-grade and home-made masks – found that they could all potentially help limit the spread of Covid-19.

However, some of the masks enabled strong jets of air to escape from the back and sides, researchers found.

The findings could aid policymakers producing guidance on the wearing of masks to help combat the virus, which can be spread in small droplets of water in people’s breath, experts said.

A team led by engineers at the University of Edinburgh assessed different face coverings using a technique – called Background Oriented Schlieren imaging – that enables scientists to measure the distance and direction travelled by air expelled when a person breathes or coughs.

Measurements were taken from people wearing different face coverings while standing or lying down, and from a manikin connected to a cough-simulating machine.

Researchers found that all face coverings without an outlet valve reduce the forward distance travelled by a deep breath out by at least 90 per cent.

A type of mask commonly worn by workers exposed to fine dust – called a respirator mask – was shown to provide protection to the wearer. However, the valves on these masks that made breathing easier could potentially allow infectious air to spread considerable distances in front, the study suggested.

Surgical masks and the tested hand-made masks were found to limit the forward flow of a breath out, but also generate far-reaching leakage jets to the side, behind, above and below. Heavy breathing and coughing, in particular, were shown to generate intense backward jets.

Only masks that form a tight seal with the face were found to prevent the escape of virus-laden fluid particles, the team says.

Researchers found that full-face shields worn without masks enabled the release of a strong downward jet.

The team also discovered that a regular medical procedure known as extubation – the removal of a breathing tube used during anaesthesia and when patients are on a ventilator – may increase the risk of spreading Covid-19.

Simulations showed that the coughing that regularly accompanies extubation caused people nearby to be enveloped in the patients’ exhaled air. This puts clinicians and others at high risk of exposure to the virus, the team said.

The research will be published as a preprint paper at 01.00 BST on Thursday 21 May. An advance copy of the paper is available here: https://bit.ly/36fOqbE. It also involves NHS Lothian clinicians and Heriot-Watt University.

Dr Ignazio Maria Viola, of the University of Edinburgh’s School of Engineering, who coordinated the project, said: “I have generally been impressed by the effectiveness of all the face coverings we tested.

“However, we discovered that some face coverings allow the emergence of downward or backward jets that people are not aware of and that could be a major hazard to others around them.”

Dr Felicity Mehendale, a surgeon at the Centre for Global Health at the University of Edinburgh’s Usher Institute, said: “It was reassuring to see the hand-made mask worked just as well as the surgical mask to stop the wearer’s breath flowing directly forwards.

“This suggests that some hand-made masks can help to prevent the wearer from infecting the public. But, the strong backward jets mean you need to think twice before turning your head if you cough while wearing a mask; and be careful if you stand behind or beside someone wearing a mask.”

Scottish Conservative health spokesman Lothian MSP, Miles Briggs, said:  “The use of a face mask to reduce the possible transmission of Covid-19 is apparent and now we have the science to back it up.

“As we move out of lockdown measures such as people using face masks will be vital for keeping the R number down.

“This is a very worthwhile piece of research by the University of Edinburgh on the effectiveness of different face masks.”