Infectious diseases experts agree: the Delta variant’s airborne transmission requires only fleeting contact with an infected person. Do we need tighter controls and quicker responses around lockdowns and border closures?
In Australia, Queensland’s chief health officer, Dr Jeannette Young, echoed this concern, noting that very fleeting contact leads to the transmission of the Delta variant – as reflected by the recent outbreak across the ditch.
At the start of this pandemic, it was about 15 minutes of close contact that was of concern, now it looks like it is five to 10 seconds. The risk is so much higher now than it was only a year ago.
“Fleeting contact” is an accurate description. According to Professor Nancy Baxter, head of the University of Melbourne’s school of population and global health, it underlines the airborne nature of both the original and Delta variants of the virus.
The World Health Organisation formally acknowledged the airborne spread of COVID-19 back in April. They reviewed mounting scientific evidence that infection can occur when viral particles remain “suspended in the air or travel farther than one metre”. Further laboratory studies have found that particles of the virus can linger in the air in aerosolised form for up to 16 hours.
In indoor settings, airborne transmission could occur even when there is no fleeting contact, as respiratory aerosols accumulate in the same way cigarette smoke does.
“In an indoor space where there is poor ventilation, somebody with the infection could have come and gone, but the virus still lingers in the air,” said Professor Raina Macintyre, head of the biosecurity research programme at the University of New South Wales’s Kirby Institute.
Shared air is a problem, so mask up, open windows/doors to get airflow when sharing space with others, and regularly check air conditioning ventilation and cleaning filters.
Here in New Zealand, messaging to the public has been concentrated around hand washing, using hand sanitiser and the uptake of the COVID-tracer app.
Is it time to get the message out to people that the virus is in the air we breathe?
With the new Delta strain spreading quickly in countries that thought they had COVID-19 under control should we make changes in a pre-emptive strike? Have we reached the point where we should promote the mandatory wearing of masks in shared spaces indoors and on public transport throughout the country?
Rather than see if we can dodge a bullet here in New Zealand, we should adapt to the new 2021 landscape of the virus and learn from what is happening in other countries.
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