Many of us are using home delivery more frequently as part of social distancing — be it parcels, letters or online shopping. But should we be worried about catching coronavirus from the surfaces of these deliveries?
Researchers have recently tested how well the new coronavirus survives in the air as an aerosol, and on different surfaces including cardboard, likely to be the material for many of our packages.
The researchers found that the virus was no longer detectable 24 hours after it was placed on cardboard. There was a range on other surfaces, from about 4 hours on copper to 3 days on plastic and stainless steel.
The US Centers for Disease Control and Prevention (CDC) has said there is likely very low risk of spread from products or packaging that are shipped over a period of days or weeks, with the WHO making a similar statement.
The findings do highlight the importance of following advice on frequent washing your hands, particularly after touching surfaces that may be contaminated.
Where did the story come from?
Since the start of the novel coronavirus outbreak people have been concerned about the risks from packages. Initially concerns centred on packages coming from areas where the infection had first taken hold such as China, but as the virus is now more widespread so are the concerns.
What is the basis for the claim?
A recent study by researchers at US institutions including Princeton and the National Institute of Allergy and Infectious Diseases has looked at how long the new coronavirus SARS-CoV-2 lives on surfaces and in the air.
They created aerosols containing the virus and also placed the virus on 5 different surfaces under controlled conditions in the laboratory and tested how long it remained potentially infectious. They checked for infectivity of the virus from the aerosol for up to 3 hours, and on the surfaces for up to a week, with each experiment repeated 3 times. All experiments were carried out at 21 to 23°C. The aerosol experiment was carried out at 65% relative humidity, and the surface experiments at 40% relative humidity.
When they tested the aerosol, they found that the number of infectious virus particles in the air decreased over 3 hours, but was still present.
The researchers tested how the virus behaved on copper, cardboard, stainless steel, and plastic. They found that it survived longer on plastic and stainless steel (up to about 3 days) than on cardboard and copper (no virus detected after 24 hours and 4 hours respectively).
The results for cardboard varied more across the 3 experiments than for other surfaces, so this made the researchers more cautious about them.
What do trusted sources say?
The WHO reports that studies suggest that coronaviruses may persist on surfaces for between a few hours and several days, and that this may vary based on factors like the type of surface, or temperature and humidity of the environment. They say that there is both a low chance of commercial goods being contaminated by an infected person and or catching the virus off of a package that has been moved, travelled, and been exposed to different conditions and temperature.
The US CDC provides a similar statement, saying that the risk from packages that have been shipped over a period of days or weeks is likely to be low.