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Australia; NSW; QLD
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Expert Reaction
These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.
Professor Johnson Mak is a virologist at Griffith University's Institute for Glycomics
The Delta variant (B.1.617.2) originated in India, the fourth major variant of SARS-CoV-2 that has a major health impacts at a population level.
People need to remember that COVID is a 'probability/numbers' game. From what I can see, Victorians are doing a wonderful job.
The conversation should NOT be on ‘why Melbourne’, rather 'what we can do positively as a collective/nation/citizens'. Time will reveal when the Delta variant first arrived on Australian shores.
I strongly encourage everyone go to get their vaccine shots ASAP, which is the best way to stop COVID. Both the AstraZeneca version and Pfizer version of COVID vaccines are highly effective.
Recent data shows 'Even a vaccine that had lower efficacy in clinical trials (than AstraZeneca- and Pfizer- versions of COVID vaccine) can dramatically control the pandemic virus. A Brazilian town experiment shows mass vaccination can wipe out COVID-19', but it will only work if we (as a collective/nation/citizens) take them.
Dr Stuart Turville is an Associate Professor in the Immunovirology and Pathogenesis Program at UNSW Sydney's Kirby Institute
What does it mean that they’ve now found Delta in Melbourne? What do we know about this variant?
Delta is the genetic “cousin to Kappa”. The key difference is that it has a fitness gain that enables the virus to bind cells better. Where Kappa had a change called 484q, this has 478k. If we remember back to our second wave we had a similar virus called variant 20F. It also had a similar change called 477n. Changes in these regions (477 and 478) are observed to increase affinity to the primary receptor Ace2. In the lab under controlled conditions, we do see Delta to be approximately 1.4 times fitter than Kappa. Whilst this is a laboratory observation, the displacement of Kappa by Delta in India does support it to be a fitter variant in populations where vaccine immunity is low.
Is it a coincidence that we now appear to have two separate outbreaks in Melbourne?
The numbers of Delta are increasing globally. Like what we have seen with Alpha in early 2021, it just means we will see more Delta cases in quarantine and that if there is a breach, it will be highly probable to be that variant.
With sequencing unable to link this cluster to hotel quarantine, where could this variant have come from? The first family recently returned from a trip to Jervis Bay, NSW
It is best we let the contact tracers and sequencing teams do their job to map out where it has come from. They will be the first to know. Detective work like this takes time.
Health authorities believe the virus was transmitted between two Year 5 students at school. Is this surprising?
It is something that we need to keep an eye on globally. Viruses that increase their affinity for receptors (become more sticky) need to be looked at carefully as this can manifest as changes in how they not only spread but also who they can infect and causes disease in.
This needs to be documented accordingly and is best done by those compiling global observations of prevalence and disease course. Whilst Delta is listed as a variant of concern, the data from vaccinated populations in the UK are promising. Vaccination is our key defence and until we have higher rates, we need to treat this variant and all variants like we have done in 2020.
