New South Wales and Victoria continue to grapple with rising Covid-19 daily cases despite both states being in hard lockdowns for weeks.
Professor Tony Blakely. Photo: Billy Wong/University of Auckland
It has raised questions as to whether it's time Australia accepts the Delta strain and learns to live with it.
NSW is setting state and nationwide records for new cases but has started to ease restrictions for those fully vaccinated.
A top epidemiologist in Melbourne says while it's too late for NSW to work towards an elimination strategy, there's still time for Victoria and New Zealand.
University of Melbourne School of Population and Global Health Professor Tony Blakely spoke to Worldwatch'sPerlina Lau.
"The hand has been forced in NSW now. They have had to learn to live with the virus earlier than they would have liked" - Professor Tony Blakely
Q: Worldwatch: You've publicly supported the elimination strategy in Australia - is this still the case?
A: "So the elimination strategy is what we are using. But at some point we pivot away from it to letting in the virus - hopefully on our terms when we get to 80 percent vaccination rates.
"However, the hand has been forced in NSW now. They have had to learn to live with the virus earlier than they would have liked. And it may have been forced in Victoria and New Zealand as we speak.
"At the moment Victoria's hand is being forced because we are not controlling the virus as well as we did in the last lockdown for a range of reasons; the two most obvious being that this virus is so slippery that sometimes you are going to be unlucky.
"The second is that compliance has fallen away in Victoria. You only need 10 percent of your population - with a couple of infected people among them - to be mixing more than is set out in the stay at home orders and you have a problem."
Q: NSW started with a softer lockdown and then changed it over time. What do you think will happen after September?
A: "It is hard to say. What should happen is that they incrementally release their restrictions as vaccination coverage goes up. So as the vaccination coverage goes up, on top of current lockdowns, it will drive the effective reproductive rate - the RF - down, a bit more each day.
"It will drive it down from one to 0.9 then 0.8 and a bit more each day. And once you have driven down to around 0.8 the case numbers will come down and you can incrementally let go and you can go from a hard lockdown to a soft lockdown like a saw tooth - you can come out of it by trying to make sure that the RF does not go above one - or not by much.
"The vaccination rate should drive it down. As each day goes by and more people are vaccinated your RD comes down a little bit each day."
Q: Do you think NSW, Victoria and even NZ need to accept the virus and learn to live with it?
A: "New South Wales has no choice, not quite yet for Victoria. For Victoria we have by Australian standards, a very hard lockdown in place until September 2 and I am fully supportive of the government's approach; to do things like close playgrounds and give it a really good push.
"But things aren't tracking as well as I and everybody else hoped. When September 2 comes around, if the numbers are not a lot lower than they are now, we are going to have to reconsider our options; do we start to live with the virus or do we stay in hard lockdown for another couple of weeks and try to get rid of these cases - even though we haven't succeeded already.
"For New Zealand, you are not that far advanced yet; your outbreak is reasonably early and you should be going absolutely hard for another couple of weeks before you accepted living with the virus, when you get to 80 percent vaccination coverage."
Q: Is there fatigue in Victoria?
A: "Absolutely. Two weeks ago I just happened to have to drive my son to a flat, and there were people in Fitzroy sitting all over the footpaths, outside coffee bars, outside pita bread shops, outside pubs, with masks down so it was essentially like a garden bar on the footpath.
"That is fatigue, that is people getting sick of the lockdown. That is why I support going to September 2 with harder measures to see if we can turn it around. But come that date if we are not winning, then we are going to have to rethink about how we do this. We can't stay in this hard lockdown forever."
Q: If NSW, and maybe Victoria, have to learn to live with Delta is there any risk that hospitals won't be able to keep up with the number of infections?
A: "Contact tracing is very important in this mix. What happens with contact tracing is it functions best with say 10 cases per day. At 10 cases per day they are probably finding ninety percent of each contact's infected contacts within three days. And it works well. But once you get up to 100 or 200 even a 1000 cases is your workforce is overstretched.
"What that means is that contact tracing really helps when it is going well to push the reproductive rate below one on top of whatever social measures or lockdown, you have got. But when the infection rate is much higher, the lockdowns are still doing the same heavy lifting because they scale, but the contact tracing is no longer doing as much and you lose control.
"So the contact tracing is critical here. If you are going to have to live with the virus - at least until you have a very high vaccination coverage and perhaps some natural immunity from natural infection - then you want to keep infections at a level that does not completely overwhelm contact tracing. Otherwise, we lose a tool out of our toolkit.
"The next six months is about getting to a point where the vaccination rate is very high and, where possible, trying to keep zero transmission for as long as you can. Where you pivot you have three options.
"The first is that laid out in the Skegg Report in New Zealand; it is where you open your borders up but you do it very cautiously and you try to re-eliminate each time you have another outbreak, trying to minimise the impact of Covid on the population. That is a possible trajectory; I actually think it is technically quite difficult because you spend a lot of time in lockdown which makes it politically difficult as well.
"The next option is where you do classic, textbook flattening the curve, letting the case numbers up to the maximum your health services can tolerate. What happens at that point is that your health services are stretched with lots of hospitalisation and ICU admissions - there will be deaths. The idea of that option is that after a year you would have topped up your vaccine induced immunity with natural infection-induced immunity and it achieves something that looks like herd immunity. You do exit the pandemic but it is painful to get there.
"The middle option which I believe Australia will take and I suspect New Zealand will fall into is whereby you take a halfway position between re-eliminating and so you do a tight suppression strategy, keeping the case numbers in New Zealand at say less than 200 per day and in Australia at less than a thousand per day. What that does is it keeps your options open for a bit longer because there are new vaccines which come along or new treatments.
"You have bought time for those to develop which you can then use in year two before you exit. But that middle road will not induce enough natural immunity that you exit with herd immunity at the end of it in the first year from both vaccine and natural infection. Nevertheless, I suspect that is the option Australia and New Zealand will end up taking - the middle road."