Thursday , December 7 2023

Corona virus is a pandemic now. It can travel twice as far as official ‘safe distance’ and stay in air for 30 minutes, Chinese study finds

Today, the World Health Organisation, WHO,  has called the COVID-19 infections a pandemic. The viral disease that has swept into at least 114 countries and killed more than 4,000 people is now officially a pandemic, the World Health Organization announced Wednesday. “This is the first pandemic caused by coronavirus,” WHO Director-General Tedros Adhanom Ghebreyesus declared at a briefing in Geneva.

It’s the first time the WHO has called an outbreak a pandemic since the H1N1 “swine flu” in 2009.

Authorities advise people to stay 1-2 metres apart, but researchers found that a bus passenger infected fellow travellers sitting 4.5 metres away

The scientists behind the research said their investigation also highlighted the importance of wearing face masks because of the length of time it can linger. The coronavirus that causes Covid-19 can linger in the air for at least 30 minutes and travel up to 4.5 metres – further than the “safe distance” advised by health authorities around the world, according to a study by a team of Chinese government epidemiologists. The researchers also found that it can last for days on a surface where respiratory droplets land, raising the risk of transmission if unsuspecting people touch it and then rub their face.

The length of time it lasts on the surface depends on factors such as temperature and the type of surface, for example at around 37C (98F), it can survive for two to three days on glass, fabric, metal, plastic or paper.

These findings, from a group of official researchers from Hunan province investigating a cluster case, challenge the advice from health authorities around the world that people should remain apart at a “safe distance” of one to two metres (three to six and a half feet). Their work was based on a local outbreak case on January 22 during the peak Lunar New Year travel season. A passenger, known as “A”, boarded a fully booked long-distance coach and settled down on the second row from the back.

The passenger already felt sick at that point but it was before China had declared the coronavirus outbreak a national crisis, so “A” did not wear a mask, nor did most of the other passengers or the driver on the 48-seat bus.

Several passengers became infected during the four-hour bus journey.

China requires closed circuit television cameras to be installed on all long-distance buses, which provided valuable footage for researchers to reconstruct the spread of the virus on the bus, whose windows were all closed.

“It can be confirmed that in a closed environment with air-conditioning, like in an aircraft, the transmission distance of the new coronavirus will exceed the commonly recognised safe distance,” the researchers wrote in a paper published in peer-review journal Practical Preventive Medicine last Friday. The paper also highlighted the risk that the virus could remain afloat even after the carrier had left the bus. The scientists warned that the coronavirus could survive more than five days in human faeces or bodily fluids.

They said the study proves the importance of washing hands and wearing face masks in public places because the virus can linger in the air attached to fine droplet particles.

Hu Shixiong, the lead author of the study who works for the Hunan Provincial Centre for Diseases Control and Prevention, said the security camera footage showed patient “A” did not interact with others throughout the four-hour ride. But by the time the bus stopped at the next city, the virus had already jumped from the carrier to seven other passengers. These included not only people sitting relatively close to “patient zero”, but also a couple of victims six rows from him – roughly 4.5 metres away. They all later tested positive, including one passenger who displayed no symptoms of the disease.

After these passengers left, another group got on the bus about 30 minutes later. One passenger sitting in the front row on the other side of the aisle also became infected.

This article appeared in the South China Morning Post print edition as: “Spike in global cases predicted”
Updated: 4:15pm, 11 Mar, 2020

Dahlia Hassell on DCNA staff
Reminder: Changes in BES Healthcare Insurance claims as of January 1st, 2020