Virus spread that’s left scientists baffled
It was early one morning when residents at Hong Mei House - an apartment block in Hong Kong - were ordered to evacuate over coronavirus fears.
Five residents living on different floors had been confirmed as having the deadly disease, but how they contracted it still has scientists scratching their heads.
That's because most international experts, and Australian government for that matter, currently believe the COVID-19 is spread via droplets when an infected person sneezes or coughs.
However, the case of Hong Mei House, has raised the possibility that the coronavirus could be spread through airborne particles over long distances.
The first two people to contract the virus in the building, a 62-year-old woman and a 75-year-old man several days later, lived 10 floors apart but were on the same vertical block of apartments.
Now Professor Raina Macintyre, an Australian scientist who's the head of the biosecurity program at the UNSW Kirby Institute, has looked at the spread.
She said it would be wise to assume from it that the new coronavirus may have airborne transmission - much like SARS.
"SARS was documented to be spread by airborne, droplet and contact routes," Professor MacIntyre wrote in a paper released this week.
"A report of transmission of COVID-19 from floor to floor of a building in Hong Kong has raised questions about long-range aerosol transmission.
"(The novel coronavirus) is a respiratory virus, with higher viral loads in the lower respiratory tract compared to the upper, consistent with the possibility of airborne transmission.
"It is therefore prudent (well judged) to assume that transmission may be by contact, droplet and possibly airborne modes."
The spread in Hong Kong also set off alarm bells among health officials because of the possibility that the virus could have been spread through pipes in the building.
If this is found to be the case, it could lead to hundreds of people becoming infected in the safety of their own homes in a densely populated city like Hong Kong.
It has drawn comparisons to the 2003 SARS outbreak, when there were more than 300 infections and 42 deaths after defective plumbing allowed the virus to spread through the city's Amoy Gardens housing estate.
However, an investigation into the spread is ongoing and it is too early to say how it happened exactly.
University of Hong Kong microbiologist Yuen Kwok-yung told Hong Kong media one possibility was that a broken exhaust pipe had allowed the virus to spread throughout the building.
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AUSTRALIA'S DEATH RATE COULD BE HIGHER THAN CHINA'S
In the same report, Professor Macintyre warned the coronavirus death rate could soar beyond the estimated 3 to 4 per cent mortality rate in Australia due to our ageing population.
She said urgent action was needed to protect older generations from the deadly disease.
"With an ageing population and a more severe illness in older people, Australia may see a proportionately greater morbidity and mortality impact than China," she said.
"We should persist with all feasible measures for as long as possible," Prof Macintyre said.
"Travel bans and quarantine are proven interventions, and especially critical for infections with pre-symptomatic or asymptomatic transmission."
Australia's three deaths to date have all been elderly people, aged 78, 82 and 95. The latter two were from the Dorothy Henderson Lodge aged care facility in Macquarie Park, where several residents were placed into isolation after a nurse who worked there contracted the virus.
Prof Macintyre warned that areas with a high density of people could be breeding grounds for the virus, adding that unnecessary large public events should be avoided.
"Sites where young people congregate such as schools, universities, sporting and entertainment venues would be sites of more intense transmission, and an outbreak in an aged care facility has already occurred in Australia."
"The public health goal is to prevent the epidemic becoming sustained in Australia, or if that is not possible, to delay it and reduce the total number of cases using all available interventions," she added.