New coronavirus can persist in air for hours, on surfaces for days: study

Published March 18, 2020
A worker sprays disinfectant to sanitize a public bus as a preventive measure against COVID-19 in Kathmandu on March 18. — AFP
A worker sprays disinfectant to sanitize a public bus as a preventive measure against COVID-19 in Kathmandu on March 18. — AFP

The highly contagious novel coronavirus that has exploded into a global pandemic can remain viable and infectious in droplets in the air for hours and on surfaces up to days, according to a new study that should offer guidance to help people avoid contracting the respiratory illness called COVID-19.

Scientists from the National Institute of Allergy and Infectious Diseases (NIAID), part of the US National Institutes of Health, attempted to mimic the virus deposited from an infected person onto everyday surfaces in a household or hospital setting, such as through coughing or touching objects.

They used a device to dispense an aerosol that duplicated the microscopic droplets created in a cough or a sneeze.

The scientists then investigated how long the virus remained infectious on these surfaces, according to the study that appeared online in the New England Journal of Medicine on Tuesday — a day in which US COVID-19 cases surged past 5,200 and deaths approached 100.

The tests show that when the virus is carried by the droplets released when someone coughs or sneezes, it remains viable, or able to still infect people, in aerosols for at least three hours.

On plastic and stainless steel, viable virus could be detected after three days. On cardboard, the virus was not viable after 24 hours. On copper, it took 4 hours for the virus to become inactivated.

In terms of half-life, the research team found that it takes about 66 minutes for half the virus particles to lose function if they are in an aerosol droplet.

That means that after another hour and six minutes, three-quarters of the virus particles will be essentially inactivated but 25 per cent will still be viable.

The amount of viable virus at the end of the third hour will be down to 12.5pc, according to the research led by Neeltje van Doremalen of the NIAID’s Montana facility at Rocky Mountain Laboratories.

On stainless steel, it takes 5 hours 38 minutes for half of the virus particles to become inactive. On plastic, the half-life is 6 hours 49 minutes, researchers found.

On cardboard, the half-life was about three-and-a half-hours, but the researchers said there was a lot of variability in those results “so we advise caution” interpreting that number.

The shortest survival time was on copper, where half the virus became inactivated within 46 minutes.

Opinion

Chained to the rivers
Updated 18 Jan 2021

Chained to the rivers

There are many state actors who must shoulder the blame for their present condition.
Brave new world
18 Jan 2021

Brave new world

Covid-19 is bringing about a reassessment of the role of markets.
The war comes home
18 Jan 2021

The war comes home

The Capitol riots included several former members of the US military.

Editorial

Updated 18 Jan 2021

More ignominy for PIA

Decades of mismanagement, nepotism and political opportunism were bound to take their toll.
18 Jan 2021

Agriculture woes

AGRICULTURE is the lifeline of Pakistan’s economy. It is a source of livelihood for two-thirds of the country’s...
18 Jan 2021

Internet access

AS the Covid-19 pandemic rages on, and shows few signs of dissipating, one of the many lessons policymakers should ...
Updated 17 Jan 2021

Foreign funding case

THE Election Commission of Pakistan has summoned both the PML-N and PPP on Monday in connection with the foreign...
17 Jan 2021

Vaccine procurement

ALL eyes are on the government as it pledges to roll out the Covid-19 vaccination programme to about 80m citizens by...
17 Jan 2021

Makli ‘renovation’

THERE are fears that the recently conducted ‘renovation’ work carried out at the Makli necropolis may rob the...