Coronavirus may spread across half of hospital surfaces in just 10 hours, new study reveals
It may be possible for Covid-19 to spread across nearly half the surfaces of a hospital ward within just 10 hours from a single spot. Using a virus that does not infect humans, researchers from the University College London (UCL), and Great Ormond Street Hospital (GOSH) found that virus DNA left on a hospital bed rail was present in nearly half of all sites sampled across a ward within 10 hours and persisted for at least five days. The team wanted to safely simulate how SARS-CoV-2, the virus that causes Covid-19, may spread across surfaces in a hospital. Accordingly, instead of using the novel coronavirus, they artificially replicated a section of DNA from a plant-infecting virus, which cannot infect humans, and added it to a milliliter of water at a similar concentration to SARS-CoV-2 copies found in infected patients' respiratory samples.
Researchers placed the water containing this DNA on the handrail of a hospital bed in an isolation room -- that is, a room for higher-risk or infected patients -- and then sampled 44 sites across a hospital ward over the following five days. They found that after 10 hours, the surrogate genetic material had spread to 41% of sites sampled across the hospital ward, from bed rails to door handles to armrests in a waiting room to children's toys and books in a play area. This increased to 59% of sites after three days, falling to 41% on the fifth day.
“The surrogate DNA persisted on surfaces, with 41% positive sites on day 5, implying a combination of poor cleaning, movement of patients, and potential re-inoculation of the surrogate DNA following patient movement between the isolation room and clinical areas. Locating the surrogate DNA outside the isolation room highlights how easily surfaces play a role in transmitting infectious agents, even from rooms designed to help containment,” says the study published in the Journal of Hospital Infection. The analysis shows that the highest proportion of sites that tested positive for the virus DNA came from the immediate bedspace area, which includes 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.
“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,” says senior author of the study, Dr Lena Ciric from UCL, in the analysis. The researchers say that like SARS-CoV-2, the surrogate used for the study could be removed with a disinfectant wipe or by washing hands with soap and water. They say cleaning and handwashing represent the first line of defense against the virus and the latest findings are 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.
“This study highlights the role of surfaces as a reservoir of pathogens and the need to address requirements for surface cleaning. It is important to consider all methods of transmission, including the risk from surfaces. To reduce the risk, the first line of defense for preventing the spread of SARS-CoV-2, and other potential pathogens, is effective cleaning. SARS-CoV-2 is an enveloped virus; as such, it is very susceptible to most cleaning agents, which destroys the envelope and deactivates the virus,” says the research team.
According to the US Centers for Disease Control and Prevention (CDC), the Covid-19 virus is thought to spread mainly from person-to-person, who are in close contact with one another (within about 6 feet). It spreads through respiratory droplets produced when an infected person coughs, sneezes, or talks. It may be possible that a person can get Covid-19 by touching a surface or object that has the virus on it, and then by touching one’s mouth, nose, or eyes. In a previous study, experts from the National Institutes of Health (NIH) and CDC found that Covid-19 can survive in the air for almost three hours. They also found that the virus can remain viable on surfaces such as plastic and steel for up to three days.