A new study has demonstrated how quickly virus DNA can spread throughout a hospital.
A new study has demonstrated that virus DNA can spread across a hospital ward in 10 hours.
The study, published as a letter to the editor in The Journal of Hospital Infection, confirms the importance of good hygiene practices, including wiping down surfaces to limit the spread of Sars-CoV-2.
Sars-CoV-2 primarily spreads in droplets expelled from a person’s nose or throat.
Experts believe these droplets do not travel more than 1 or 2 meters (m) in the air. So, it is important to keep a physical distance of 6 feet (2 m) from people when outside the home to reduce the spread of the virus.
However, correspondence to the New England Journal of Medicine indicates that SARS-CoV-2 can survive on stainless steel and plastic for up to 3 days.
If a person touches a surface that has the virus on it and then touches their face, they are at risk of contracting the virus. They can also pass the virus on to other people who touch the contaminated surfaces.
Consequently, the World Health Organization and other public health bodies have stressed the importance of regular hand washing.
Washing the hands after potentially coming into contact with the virus helps reduce a person’s risk of transmitting or contracting the virus.
These hygiene practices are even more critical in a hospital context, where there is likely to be high numbers of people who are vulnerable to the virus or people who have it and could transmit it.
As well as maintaining social distance and regular hand washing, it is crucial to wipe down surfaces. An article in Infection Prevention in Practice notes that commonly used hospital-grade disinfectants are an effective way to kill the virus in clinical environments.
To explore how surfaces can transmit the virus, the authors of the present study created a surrogate of Sars-CoV-2, using a short section of DNA from a virus that can affect plants but not humans.
The researchers found that following hand washing protocols effectively removed the surrogate. The researchers also found that wiping a surface with a single alcohol wipe removed up to 99.84% of the surrogate.
The authors placed 1.15 billion pieces of the surrogate in 0.1 millimeters of liquid to simulate a mucus droplet. They applied this droplet to the handrail of a hospital bed in a pediatric isolation room on a Monday morning.
The researchers used a cotton swab to take samples from across the ward every evening for 5 days.
They took 44 samples each per day, including 20 from the space immediately around the bed, eight from the wider area around the bed, such as the handles of the cubicle door, seven from clinical areas, and nine from the general ward areas, such as the reception.
They then analyzed the samples for the DNA of the surrogate virus.
Virus DNA spread in under 10 hours
Analysis of the samples detected that the virus DNA had moved from the isolation room to 41% of sample surfaces throughout the ward within the first 10 hours. Surfaces included bed rails, door handles, armrests, and children’s books and toys in the waiting area.
After 3 days, the DNA of the virus had transferred to 52% of surfaces, returning to 41% by the fifth day.
The team found the majority of the positive samples near the handrail on the bed in the isolation room. In fact, bed rails throughout the were among the most common sites for the surrogate. However, they also found a significant number of the surrogate virus in clinical areas.
According to Dr. Lena Ciric, of University College London (UCL) in the United Kingdom and a senior author of the study, “[o]ur 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.”
For Dr. Elaine Cloutman-Green, of UCL, a co-author of the study and a lead healthcare scientist at Great Ormond Street Hospital, also in the U.K., the findings evidence the importance of good hygiene practices.
Dr. Cloutman-Green 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 hand washing represent our first line of defense 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).”
It is important to note that while the study clearly explains how far the virus’s DNA spread throughout the hospital, it does not tell us how many people could have contracted the virus from this spread.
For example, scientists do not know how much SARS-CoV-2 a person needs to get before they develop COVID-19. However, The Centre for Evidence-Based Medicine (CEBM) indicate that amount of the virus a person has exposure to in the first instance might affect the severity of the COVID-19 symptoms that they then develop.
It is also possible that the Sars-CoV-2 virus may behave differently to the surrogate virus when it spreads throughout a hospital.
Nonetheless, the study confirms that following good hygiene protocols, including regularly cleaning surfaces, washing hands, and using personal protective equipment, is likely to reduce the spread of viruses on surfaces in hospital environments.
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