KUALA LUMPUR, June 25 — Australian government officials have warned how easily the Delta coronavirus variant spreads, in mere seconds, after fleeting encounters between strangers at a mall in the state of New South Wales resulted in transmission of the disease.
New South Wales premier Gladys Berijiklian described the encounters as “scarily fleeting” after CCTV footage showed the transfer of the virus between two people who briefly walked past each other while shopping at Westfield Bondi Junction in Sydney.
“Literally people not even physically touching each other but fleetingly coming into the same airspace has seen the virus transfer from one person to another,” the premier said, as reported by local media ABC News. “That’s how contagious it is.”
Two other Covid-19 cases were believed to be infected in similar fashion.
Griffith University virologist Lara Herrero was quoted by ABC News as saying that in the Sydney case captured by CCTV, the person got infected when breathing in the virus that lingered in the air.
Dr Jeannette Young, chief health officer of Queensland, similarly highlighted the speed and ease of the spread of the Delta variant with “very fleeting contact” in some cases.
“If you remember at the start of this pandemic, I spoke about 15 minutes of close contact being a concern,” she was quoted saying.
“Now, it looks like it’s five to 10 seconds. That’s a concern. The risk is so much higher now than it was only a year ago.”
New South Wales health minister Brad Hazzard further illustrated the variant as “a gold medalist when it comes to jumping from one person to the other”, as quoted by The Guardian.
Visual proof of the transmission has prompted health authorities to request those who were at the Sydney mall on June 12 and 13 to get tested for Covid-19 and minimise their movement.
Dr Young announced Wednesday that Queensland would shut its borders to people from Greater Sydney, the Central Coast, Blue Mountains, Wollongong and Shellharbour as the state expanded its list of hotspots.
The World Health Organization (WHO) in April acknowledged the airborne spread of Covid-19. It stated that the virus can spread when viral particles remain “suspended in the air or travel farther than one metre”.
A study published by the Centers for Disease Control and Prevention (CDC), based on experiments conducted across several laboratories, found that the virus can linger in aerosol form for up to 16 hours.
In an op-ed in The Sydney Morning Herald, University of New South Wales’s Kirby Institute head of the biosecurity research program Professor Raina Macintyre said that airborne transmission in indoor settings can occur even in the absence of fleeting contact.
“Think of other people’s exhaled breath like cigarette smoke – it accumulates if ventilation is inadequate, and you will breathe it in,” she said.
The Delta strain, first detected in India in October last year, is now detected in 85 countries. It is expected to be a dominant Covid-19 variant — overtaking Alpha — if the current trend continues.
WHO’s Covid-19 Weekly Epidemiological Update on June 22 stated that the variant Alpha has been reported in 170 countries, territories or areas, Beta in 119 countries, Gamma in 71 countries and Delta in 85 countries.