(Image: AAP/Mick Tsikas)

It is scientifically questionable whether it really is darkest just before dawn, but let’s use some licence because it’s certainly dark in Victoria and New South Wales right now.

But as Sydney and Melbourne endure their strictest lockdowns since the pandemic began, the larger battle of when Australia will start “living with COVID” continues to rage. 

Delta’s fast incubation period and high transmissibility has killed the dream of COVID zero and herd immunity. This has meant that COVID-zero adherents have had to come up with another reason to delay opening up. Their latest? Opening with a high number of existing infections wasn’t part of the deal.

James McCaw was one of the authors of the Doherty report (but not the primary author, who was Jodie McVernon), and holds an honorary role at the Doherty Institute. He claimed that even with 70% to 80% of adults vaccinated (56% to 64% of all people), NSW wouldn’t be able to “open up” with high case numbers. 

McCaw’s view was echoed by Victorian Premier Daniel Andrews and Steven Miles, Queensland’s deputy premier, in recent days. Andrews warned: “If you don’t actively suppress this virus then when you do open up, we will have scenes the likes of which none of us have ever experienced in our hospitals.”

McCaw said: “NSW needs to work to continue to reduce those case numbers and get the outbreak under control. There is a very, very clear and coherent relationship between the targets Doherty puts forward and the response required by NSW to help us get there.”

But McCaw was quickly contradicted by Australia’s Chief Medical Officer Professor Paul Kelly, who said: “The model itself remains the same; it’s a tweak to the assumptions.”

The McCaw/Andrews/Miles’ view doesn’t make a huge amount of sense given the transmissibility of the Delta strain. If Australia lifted restrictions at even 80% adult vaccination levels, there would inevitably be a rapid spike in infections, potentially upwards of 20,000 a day, regardless of the starting number. When we open borders, even to lower-risk countries, infections will inevitably be imported. 

But there are two significant mitigating factors here.

First, vaccinations are more effective at preventing serious illness and death than infections, so we would see more mild cases, but not hospitalisations or deaths. We have seen a practice run in the past fortnight in NSW, where daily infections have increased by 300%, but ICU patients have increased by a more modest 41%, and this is with only 31% of adults fully vaccinated.

Second, vaccinations have been targeted towards the older and the at-risk (in NSW, 87% of the high-risk 70+ group have had at least one dose), which means the case fatality rate will drop significantly. In the UK, which followed a similar targeted vaccination campaign, the case fatality rate has fallen from 2% in January to about 0.3%.

While the Doherty modelling appears to have understated infection levels after reopening, the vaccination targets appear defensible given the countries which reached 64% vaccination levels (Canada and Iceland) were able to reopen with very low death rates (Israel is experiencing a third wave and has not yet even reached Doherty’s phase C target).

The arguments are becoming increasingly hostile as we move from the theoretical to the actual. Australia’s vaccination rate has morphed from slowest in the OECD to the world’s fastest (NSW is vaccinating people at a higher rate than even the UK was able to achieve). 

By the end of October, Australia is likely to have completed 38 million vaccinations, or 76% of the total population. At that level, no Western country kept their borders or their businesses closed.

It is not without irony that while Australians turn out in record numbers to get vaccinated, state premiers try to come up with new ways to ensure they remain under lock and key.

Should Australia aim for zero COVID? Let us know your thoughts by writing to letters@crikey.com.au. Please include your full name if you would like to be considered for publication in Crikey’s Your Say column. We reserve the right to edit for length and clarity.