The re-emergence of the virulent UK strain of COVID-19 in Queensland has set Australian health authorities again on edge, aware of potentially how quickly this more contagious strain could spread into the population.
Genome sequencing has confirmed a female casual cleaner from Brisbane, aged in her 20s, who contracted the UK strain locally, is suspected to have done so while working in a quarantine hotel.
She is understood to have been working while infectious for around five days after receiving a negative test on December 29.
The positive test emanating from quarantine again elevates the discussion around whether authorities are doing enough to protect, test and isolate those people who are working in critical quarantine support roles such as cleaning, hospitality and transport.
Once the case of the UK strain was confirmed, Queensland's chief health officer Dr Jeanette Young ordered a three day lockdown of the Greater Brisbane area, including Logan, Ipswich, Moreton and Redlands until 6pm on Monday.
Mask wearing is mandatory in all these areas when people have to leave their homes for essential reasons.
This is the second time the UK strain has been found in Australia, following the first detected in late November last year.
What is the UK strain of COVID-19 and what makes it different?
It's known officially as VUI-202012/01 (or the first "Variant Under Investigation" in December 2020). It is a variant of SARS-CoV-2, the virus that causes COVID-19.
The British Medical Journal said this strain had 17 changes or mutations, with the most significant being in the spike protein the virus used to bind to the human ACE2 receptor.
It is thought this change to the spike protein may be the reason why the virus spreads more easily.
Where was this strain first found?
It was first detected in Kent, in south-east England in September last year by the COG-UK (COVID-19 Genomics UK) consortium.
This consortium has been funded and resourced to investigate these types of variations.
It collects, sequences and analyses the whole genomes of virus samples from all over the UK.
Why are health authorities so concerned about it?
The concern is this variant appears to be far more transmissible. All viruses undergo genetic changes which are called mutations, which results in different variants.
Experts from the Imperial College in London say this new variant has a far higher basic reproductive number, or R number. The new variant increases the R number by between 0.4 and 0.7.
England's chief medical officer, Dr Chris Whitty, said the new variant could be up to 70 per cent more transmissible.
In the UK, the new strain was rapidly replacing other versions of the virus.
Is the new strain more severe?
Not necessarily. It's the potential speed of transmission that's of more significant concern.
Australia's chief medical officer, Professor Paul Kelly, said this variant "doesn't cause more severe illness".
"There is no increase in hospitalisation or increase in 28-day mortality," he said.
But if it spreads faster, more people get it, so that increases the load on health resources.
What's different about the new strain?
While the more transmissible nature of the variant is the key difference, a study by London's Imperial College also found in the UK, people under 20 years old made up a higher proportion of cases.
The data which supports this anomaly was being further assessed.
Will the Brisbane three-day lockdown keep it at bay?
Perhaps, but that's if they can track and trace in time. As the British example revealed, with such a rapidly transmissible variant of the virus, the spread rate is phenomenal.
Queensland Premier Annastacia Palaszczuk hoped a hard lockdown and mask mandate would buy enough time for health officials to trace the cleaner's contacts and stop the virus from spreading.
"If we do not do this now, it could end up being a 30-day lockdown," she said.
Will the three leading vaccines be effective against this new variant?
Sharon Peacock, the director of COG-UK, said: "With this variant there is no evidence that it will evade the vaccination or a human immune response."
However, immunologists have warned COVID vaccines may need to be adjusted, as occurs with seasonal flu vaccines, as the virus mutates over time.