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Research shows quick spread of virus DNA in hospital

06/08/2020

Researchers from Great Ormond Street Hospital (GOSH) and University College London (UCL) recently joined forces to safely simulate how SARS-CoV2, the virus that causes Covid-19, may spread across surfaces in a hospital. The findings, which have been published today (8th June) as a letter in the Journal of Hospital Infection, found virus DNA within 10 hours in nearly half of all sites sampled across a ward following initial contact on a bedrail – and persisted for at least five days.

Instead of using the SARS-CoV-2 virus, researchers artificially replicated a section of DNA from a plant-infecting virus, which cannot infect humans, and added it to a millilitre of water at a similar concentration to SARS-CoV-2 copies found in infected patients’ respiratory samples.

The study, which was supported by a funded UCL studentship in partnership with GAMA Healthcare and funding from the National Institute for Health Research, involved placing the water containing this DNA on the hand rail of a hospital bed in a room meant for higher-risk or infected patients. Researchers then sampled 44 sites across a hospital ward over five consecutive days.

After 10 hours, they found that the DNA material had spread to 41% of sites sampled across the hospital ward, from bed rails to door handles to arm rests in a waiting room to children’s toys and books in a play area. This increased to 59% of sites after three days, and then fell to 41% on the fifth day.

Researchers believe that this study has wider implications around infection control for hospital staff and visitors, especially now during the coronavirus pandemic. Although the study used the artificially created DNA from a virus within water, more sticky fluids, such as mucus, would likely enable the spread of SARS-CoV-2 more easily. This significantly emphasizes the need for good hand hygiene and cleaning.

Co-author Dr Elaine Cloutman-Green Lead Healthcare Scientist at GOSH and Honorary Lecturer at UCL Civil, Environmental & Geomatic Engineering said: “People can become infected with Covid-19 through respiratory droplets produced during coughing or sneezing. Equally, if these droplets land on a surface, a person may become infected after coming into contact with the surface and then touching their eyes, nose or mouth.

“Like SARS-CoV-2, the surrogate we used for the study could be removed with a disinfectant wipe or by washing hands with soap and water. Cleaning and handwashing represent our first line of defence against the virus and this study is a significant reminder that healthcare workers and all visitors to a clinical setting can help stop its spread through strict hand hygiene, cleaning of surfaces, and proper use of personal protective equipment (PPE).”

The highest proportion of sites that tested positive for the virus DNA came from the immediate bedspace area – including a nearby room with several other beds – and clinical areas such as treatment rooms. On day three, 86% of sampled sites in clinical areas tested positive, while on day four, 60% of sampled sites in the immediate bedspace area tested positive.

Dr Lena Ciric (UCL Civil, Environmental & Geomatic Engineering), a senior author of the study, said: “Our study shows the important role that surfaces play in the transmission of a virus and how critical it is to adhere to good hand hygiene and cleaning. Our surrogate was inoculated once to a single site, and was spread through the touching of surfaces by staff, patients and visitors. A person with SARS-CoV-2, though, will shed the virus on more than one site, through coughing, sneezing and touching surfaces.”

One caveat to the study is that, while it shows how quickly a virus can spread if left on a surface, it cannot determine how likely it is that a person would be infected.

With Covid-19 changing the way we live, work, play and interact with one another, it’s more important than ever that everyone does their part to keep themselves and their loved ones safe from infection.

As part of a hospital-wide effort to keep patients, their families, and staff safe while visiting GOSH, the hospital has taken a number of steps to make sure that everyone at the hospital is staying safe during Covid-19 and helping to reduce the spread of infection.  

For more information about what GOSH is doing to keep visitors and staff safe, please visit our Covid-19 hub.

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