One of Australia's first medically trained journalists, Dr Norman Swan says New South Wales is in for a rough time with Covid-19 but he sees very high immunisation rates as the best way forward.
Covid-19 has seen the Sydney investigative journalist and broadcaster thrust into a role as a trusted voice in the long pandemic.
Swan hosts the ABC's programme Health Report, and Coronacast, a podcast dedicated to informing Australians on the latest in the Covid-19 pandemic. He was one of Australia's first medically trained journalists - having trained in medicine at the University of Aberdeen in his home country Scotland.
Dr Swan said Australia has the same epidemiological view as New Zealand in that you go in hard and you go in early.
But he said there was an outbreak in the northern beaches of Sydney just before Christmas and the government did not go in hard or early.
He said it went on for about six weeks but the government got it under control.
The state government then embarked on a strategy of locking down individual suburbs to try and combat Covid-19, a strategy that had failed in Melbourne the year before, he said.
For example in New Zealand, he said it would not make sense to only lock down South Auckland because main roads separate local government areas so the entire city needs to be locked down - not just individual suburbs.
Dr Swan said that did not happen in Sydney for some time.
"And in fact even now the city is not fully locked down with the same regulation, so it's very confusing, you almost need a PhD in regulations to understand what's what where, although it's a bit simpler now than it was.
"So it's just too little, too late and it's become entrenched."
Vaccination and contact tracing
The Doherty Institute in Melbourne which researches infectious diseases has provided pandemic modelling to help guide the government's national cabinet in making decisions about how to combat Covid-19, he said.
Dr Swan said the Doherty Institute recently released a report which also has relevance for New Zealand.
He said there are a number of variables if you are modelling on something like the Delta variant.
"One is vaccination rates and the effectiveness of the vaccine in two dimensions - one is preventing serious illness and death and in preventing infection."
He said another element is TTIQ or test, trace, isolate and quarantine which is effectively the core of contact tracing and which New Zealand also does.
Dr Swan said public health and social measures or lockdown is the third element. He said the two game changers are the virus itself and immunisation levels.
"So what it actually shows is that at 70 percent immunisation, now that's of the adult population aged over 16, which is actually only 56 percent of the population - so it's not a high level of full immunisation and at 70 percent you can start to think about easing up.
"At 80 percent you can open up a little bit more, but it's highly sensitive to your contact tracing - so if your contact tracing loses control of the situation then a lot of bets are off."
He said the system is sensitive to case numbers because the Australian experience is that once you get to more than about 50 cases a day the contact tracers come under immense strain."
More than 50 cases a day and the contact tracers start to lose control of the situation, even though they are working extremely hard, Swan said.
"You've got the same situation in New Zealand as you've got here, you've got people living in multi-generational families, disadvantaged areas, needing to work, to get out there, that's exactly the same areas in New South Wales where it's concentrated, in Sydney where it's concentrated."
He said in New South Wales people are not always coming forward straight away and may have been in the community for a week and spreading the Delta virus before they are tested.
Another issue is the fact that most people with the Delta variant are spreading the virus even before they develop symptoms, he said.
He said contact tracers can have about 100 contacts for each person they are interviewing which can end up being a lot of people.
"And so in New South Wales they've still got contacts they haven't traced from early July, in Victoria they've got 70-odd cases, they've got cases they haven't pinned down for about a week - that's a lot people circulating in the community creating contacts, even under lockdown."
So what's the end game?
Swan believes things are going to get very rough in New South Wales and hospitals are already under strain.
He said there will be a lot of hospitalisations and a lot of young people and children will be infected.
But he said Australia is giving 300,000 vaccines a day which is better than the US or UK at the peak of their Covid-19 outbreaks.
He is hoping there will be 90 percent immunisation rates in Australia by December because that is what is needed against the Delta variant.
He said he does not think that New South Wales will be able to have a zero spread and it is likely Victoria could be in the same position.
"But with that level of immunisation you're not going to see many people ending up in hospital or in ICU."
He said once immunisation is more than 90 percent, no matter the number of cases they will not do as much harm in the community.
He said ultimately Covid-19 may be able to be managed like other infectious diseases but there will still need to be protections such as mask wearing, rapid antigen testing of key workers and ventilation audits in schools and offices and booster shots.