A recent paper investigates how long coronaviruses can live on different surface types. The virus appears to survive longer under colder, more humid conditions, it says. Interestingly, the authors wonder how we could kill coronaviruses.
Currently officially known as COVID-19, the novel coronavirus has been making headlines since it first came to light, late in 2019. The COVID-19 spread from China to 23 other countries and has now infected 45,171 people.
Because this strain of the coronavirus is new to science, researchers are struggling to understand how infections can be handled and how to ensure that the virus does not spread.
Because there are no clear COVID-19 therapies, a lot of experts concentrate on prevention.
Previously, scientists at the Greifswald University Hospital and Ruhr-Universität Bochum, both in Germany, gathered information from 22 coronavirus studies. Our research helps us to understand how long coronaviruses live on surfaces, and how they can be destroyed by humans.
The authors initially compiled the information for inclusion in an upcoming textbook; however, author Eike Steinmann explains that “the best approach, under the circumstances, was to publish these verified scientific facts in advance to make all information available at a glance.”
Their work, published in The Journal of Hospital Infection, focuses on coronaviruses that are responsible for two of the most recent outbreaks: severe acute respiratory syndrome (SARS) and respiratory syndrome in the Middle East (MERS).
Their paper also draws evidence from research investigating veterinary coronaviruses, such as transmissible gastroenteritis virus (TGEV), mouse hepatitis, and canine coronavirus.
How long do coronaviruses persist?
The first section of the new paper focuses on how long coronaviruses, such as tables and door handles, can survive on inanimate surfaces. The authors show that human coronaviruses can remain infectious from 2 hours to 9 days, depending on the substance and the circumstances.
Other variants of the coronavirus may remain viable for up to 28 days at temperatures of around 4 ° C or 39.2oF. The coronaviruses appeared to survive for a shorter time at temperatures of 30–40 ° C (86–104 ° F).
At room temperature, a common cold coronavirus (HCoV-229E) persisted significantly longer at 50 per cent moisture than 30% moisture. The writers say, on the whole:
“Human coronaviruses can stay infectious for up to 9 days at room temperature on inanimate surfaces. The persistence duration is shorter at a temperature of 30 ° C[ 86 ° F] or greater. Veterinary coronaviruses have been shown to persist even longer for 28 d[ays].”
The results were variable when the scientists delved into the literature about the persistence of coronaviruses on different surfaces. The MERS virus, for example, persisted over a steel surface at 20 ° C (68 ° F) for 48 hours. But TGEV lived for up to 28 days on a similar surface and at the same temperature.
Similarly, the survival of two SARS coronavirus strains on a paper surface was investigated by two studies. Another lived for 4–5 days, and the other only for 3 hours.
How to inactivate coronavirus
The authors address the best way of inactivating coronaviruses in the next section of their paper.
We conclude that coronaviruses are quickly and effectively inactivated by agents like hydrogen peroxide, ethanol, and sodium hypochlorite (a chemical in bleach).
The authors, for example, write that”[ h]ydrogen peroxide was effective with a concentration of 0.5 percent and an incubation time of 1 minute.”
“Surface disinfection with 0.1% sodium hypochlorite or 62–71% ethanol significantly reduces coronavirus infectivity on surfaces within 1 min[ute] exposure time.”
Conversely, benzalkonium chloride solutions provided conflicting results; and chlorhexidine digluconate, which people use as a topical antiseptic, has been ineffective.
The authors write that”[ t]transmission in healthcare settings can be successfully prevented by regularly taking appropriate steps.” Especially handwashing is important.
They describe how, in Taiwan, “the installation of hand wash stations in the emergency department was the only infection control measure significantly associated with the protection from the acquisition of the[ SARS coronavirus] from health care workers.”
While COVID-19 was not examined in the studies the authors summarize in this study, they believe the results are also likely to be relevant for this new coronavirus. All the human coronaviruses investigated by the research appear to be susceptible to the same chemical agents.