Scientists test whether COVID-19 has deadly new ability


There's something about COVID-19. It seems especially good at dodging many of the checks and balances aimed at impeding its spread. Now scientists are starting to understand why.

For years, groups such as the World Health Organisation have been watching the growing tide of new viruses nervously.

Ebola. SARS. Swine flu.

All were frightening. But all, fortunately, didn't cross the line into a pandemic.

They didn't quite have what it took.

But the WHO began "gaming" the impact of Disease X - a hypothetical virus - on the world's health system. The one defining characteristic it had over its real counterparts gave it real pandemic power.

To be airborne.

That's the ability to linger in the air for hours. It's also the characteristic that makes measles so incredibly infectious.

Can COVID-19 do this? Researchers are suspicious. But are not yet sure.


Measles is a template for pandemic terror.

The way this particular virus can linger in the air helps every host infect some 12 to 18 new people. Polio, rubella and smallpox are scary enough: the average infection rate for these is six.

COVID-19 isn't as bad as any of these. But it's bad enough.

On average, every patient infects two to three others. We think.

"The virus is very contagious meaning it is efficient in how it spreads," says the CSIRO's Professor Trevor Drew.

"With the research we're undertaking we're aiming to get a better understanding of transmission of the virus. At this stage transmission rates are yet to be formally determined."

And COVID-19 is continuously changing.

"This virus belongs to a group of viruses that exist not as a single virus but as a cloud of subtly different ones and if it finds a new niche to occupy, it will do that and slowly get better at replicating in the new host or alternatively it might die out," Prof Drew says.

Viruses don't only evolve incredibly quickly (an entire generation passes in just a few hours).

They can also "recombine".

This happens when a host is suffering an infection from two separate viruses at the same time.

Fragments of one can attach to another. The result is usually an unviable "chimera" of the two. But sometimes it's not.

In the case of COVID-19, research is beginning to suggest it is a "recombination" between two different viruses. One of them is likely a variety found among pangolins that is capable of entering human cells.

In this matter, COVID-19 isn't a super machine.

Its mutation rate appears to be about half that of Influenza. And influenza changes enough to make yearly flu vaccine updates effective.

"But this is the nature of the beast, this is what this type of virus does, and this is why it is challenging to get to the point of proving which drugs or vaccines might work," says the CSIRO's Dr Rob Grenfell.

Which is why the CSIRO is calling on the international community to mobilise and share their genomic sequences. These can be fed into a set of new bioinformatics algorithms to track down any new mutations as they arise quickly.

"Finding the difference among 30,000 letters of the viral genome is not an easy task, akin to finding a needle in a haystack," says Associate Professor Denis Bauer.


The measles virus is unusually small. It's so tiny, it can float about where someone has sneezed for up to two hours.

It's what researchers call an aerosol state: a particle suspended in the air.

Fortunately, most viruses can't do that. They're too big, too clunky, to be light enough.

Is COVID-19?

In these early months of combating the disease, researchers are uncertain.

There are conflicting reports. And all research papers are very much preliminary.

But the weight of evidence is tilting towards that it can. Under specific circumstances.

Early laboratory tests have proven COVID-19 can become an aerosol. But those conducted by the US National Institute of Allergy and Infectious Diseases were very specific. Very artificial. Very "worst-case" scenario.

In essence, they were very likely to find what they were looking for.

Even then, COVID-19 wasn't anywhere near the league of measles. Half its particles fell out of the air within 2.7 hours. It was almost entirely gone after a day.

In the real world, there is a multitude of confounding factors. Heat. Humidity. Just as fog (water as an aerosol) comes and goes, so too do the conditions needed to float COVID-19.

And these limitations mean air-to-air transmission is not a significant driver behind the virus' spread.

"If it could easily exist as an aerosol, we would be seeing much greater levels of transmission," epidemiologist Michael LeVasseur told medical news service STAT.

"And we would be seeing a different pattern in who's getting infected. With droplet spread, it's mostly to close contacts. But if a virus easily exists as an aerosol, you could get it from people you share an elevator with.

"Evidence (is) that the virus is predominantly spread through droplets and not as an aerosol."


COVID-19 appears to have a diverse arsenal of reproductive weapons.

That's what gives it pandemic reach.

It has been found in faeces. It's been found in secretions, such as sweat.

It has been found in the large (non-aerosol) droplets expelled by coughs. These only travel a short distance before succumbing to gravity. But those droplets then linger on tables, doors and equipment. Early tests indicate the virus can remain active for some 16 hours on plastic and 13 hours on steel.

Hence the imperative to wash your hands, regularly.

What remains to be determined precisely is how COVID-19 floats and travels in an average cough or breath.

What is its infectious range?

Is it within the 1.5 metre "social distancing" radius?

Research indicates that is generally the case.

Singaporean medical researchers regularly monitored the air in the rooms of three COVID-19 patients. No virus was detected in the air with any patient. But, in one case, it was found on ventilation fans and previously cleaned surfaces.

This indicates COVID-19 can get airborne - under rare, real-world circumstances.

Jamie Seidel is a freelance writer | @JamieSeidel

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