Health authorities scrambling to find the missing link to the Brisbane Youth Detention Centre outbreak were hopeful genomic testing would provide the answers they required to solve the mystery case at the centre of the state’s recent cluster.
Key points:Genome testing has failed to find conclusive results linking two clusters in QueenslandVirologist Kirsty Short warns “we can’t let this fester in the community unchecked”Every one person infected with coronavirus infects on average two other people
But the results have fallen short of providing any concrete answers.
The state’s Chief Health Officer initially said she believed the source of the outbreak at the youth detention centre could be linked to a cluster of coronavirus cases caused by the Logan trio who returned from Melbourne earlier this year.
But virologist with the University of Queensland Kirsty Short said the results of the genomic testing did not find enough evidence to link the two.
Dr Short said this was because the genomic test results do not show the route a specific strain of coronavirus has taken.
The strain, which appeared in the test results of both clusters, is a common strain that has been circulating widely across Victoria and New South Wales.
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Speaking at the morning coronavirus briefings, Chief Health Officer Jeannette Young conceded the strain identified was a common one.
“Although that’s almost an exact match, we’ve also found other cases elsewhere that have had that exact match,” Dr Young said.
“We can’t say definitely whether those cases are linked, but we also can’t say that they’re not.”
‘Strain shows very little mutation’
Explaining why the results were not definitive, Dr Short said tracking down the cause of a cluster was much like a balancing act between genomic testing and contact tracing.
“Short of identifying a point where these two individuals came into contact with each other, it’s very hard to say this is the source of the outbreak,” Dr Short said.
“You can’t definitely say that that is the route by which this cluster started.”
In this case, Dr Young said the mutations were not strong enough to show a match between the two cluster samples.
“There’s only one very small change between the two, which suggests that they are linked,” Dr Young said.
Genome testing has failed to find conclusive results linking the two clusters in Queensland.(AP: Ted S Warren)
Dr Short said mutations were like “signatures” which allowed scientists to differentiate between strains of the virus.
She said this genetic information was not enough to link the origins of the youth detention centre cluster to the Logan teenagers, and only tells us that it’s a common strain found interstate.
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Dr Young said she hoped further contact tracing would hold the answers many are looking for.
“[We’re] still looking to see whether, through contact tracing work, we can find any link between the two clusters,” Dr Young said.
‘We can’t let this fester unchecked’
According to Dr Short, the Queensland Government’s quick approach to implementing restrictions when cases arose made it easier for authorities to contact trace.
“They’re reacting, they’re doing the right thing. We’ve got the right plans in place,” Dr Short said.
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She said it may seem like an overreaction to implement tough restrictions when there were a low number of cases, but it decreased the chance of an outbreak.
“We know on average every infected individual infects two other individuals,” Dr Young said.
“Let’s say you have a cluster of three — it doesn’t seem very severe and maybe the response is ‘let’s not change anything, let’s keep going’.
“Each one of those three can then go on and infect another two, so now you’ve got a bigger cluster.”
Dr Short said for measures to be effective, they need to be implemented early.
“What we learnt from the situation in Victoria is that we can’t let this fester in the community unchecked, we need to act early,” Dr Short said.
She said the fewer people there were to contact trace, the easier it will be to find the missing link between the two clusters.
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