Covid-19 - Persistence of the virus in the environment and on surfaces

Articles 23/03/2020

by Antonino Napoleone, Giuseppe Scarlata, Domenico Gangemi | March 23, 2020

On 23rd March 2020, 372,563 cases are registered worldwide distributed in 168 countries, 63,927 only in Italy, of which 50,418 are currently active. This new human coronavirus has been named Severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) to distinguish it from other previously known forms of human coronavirus. Human-to-human transmission is mainly transmitted by respiratory droplets of saliva or by self-inoculation in the eyes, nose or mouth due to contact with contaminated surfaces. Investigations carried out by several studies on human coronaviruses, such as SARS-CoV-2, reveal that these viruses are able to persist on surfaces such as metal, glass or plastic for up to 9 days, but can be easily inactivated in few seconds by common disinfection procedures based on products containing 70% ethanol (like common hand sanitizers), 0.5% hydrogen peroxide and 0.1% sodium hypochlorite (bleach). There are different factors that influence the persistence of the virus in environments or surfaces, and among these, it has been seen that high temperatures (between 30°C and 40°C) drastically reduce the persistence of the virus in environments compared to lower temperatures (4°C) and that factors such as high humidity instead increase it. A recent study published in the New England Journal of Medicine analyzed the stability of SARS-CoV-2 at room temperature (21°C) and 40% relative humidity under five different environmental conditions (air, plastic, steel, copper, and cardboard). It was found that the virus can remain in the air for about 3 hours with minimal reduction of the viral load. No virus presence was detected on copper and cardboard surfaces after 8 and 24 hours respectively. In contrast, the active virus was detected after 72 hours on plastic surfaces and after 48 hours on steel surfaces, although the viral load was significantly reduced over time. Of course, there are several factors to be taken into accounts such as the source of the virus (symptomatic patients, asymptomatic patients) and the environmental contexts of daily life. The restrictions applied aim to limit the places of social interactions, but at the same time, they are concentrated on supermarkets, pharmacies, and groceries. This virus is not transmitted by contact, so intensifying procedures for disinfection and sanitization of public and private environments as well as good hand hygiene when outside the home, are key strategies to reduce drastically the spread and the presence of SARS-Cov-2 in cities. Simple strategies, but incredibly effective. Share and have faith in medical sciences rather than the media, we all need to work together to stop all of this.