12 Aug 2020

Virus modeler - NZ's Covid strategy is up to the task

From Nine To Noon, 9:25 am on 12 August 2020

The pandemic situation in Victoria shows that a Covid-19 outbreak can escalate from very small numbers initially, an economist is warning.

Wigram Capital Advisors’ Rodney Jones says his organisation has been tracking the virus since it first broke out in China and has also been providing information and advice to the Government.

A health worker conducts a test at a COVID-19 coronavirus testing centre in the suburb of Northcote in Auckland on August 12, 2020.

Photo: AFP

Even though the cases announced yesterday were in one household, this in no reason to be complacent, he says.

“Victoria began with three or four. It spent the first part of June having three or four cases on average a day and then it started to move up on the 16th of June.

“But the Victorian government didn’t respond until July 8 and so there was a missing three or four weeks where you could see a new outbreak starting to gather momentum and they sat back. And Hong Kong was very similar.”

The Covid cases detected in the community yesterday would come from the border, he says.

“Well clearly this is from the border, it didn’t come down with the rain, we had eliminated it, but we had these continual cases at the border

“And we say at the border, but that’s within New Zealand and this virus is extremely durable, extremely tricky.”
More cases are more than likely to be discovered, he says. And modelling shows when an outbreak flares up it is difficult to stamp out, he says.

“Even New South Wales with 20 a day has been given the signal that it’s about to really accelerate.
“So, we would expect more cases, there’s a clear relationship between mobility and infections, so by shutting down mobility fast there’s a greater probability of the testing to work.”

There is a clear trade-off between limiting activity and the number of cases, he says.

“So, we will just be looking over the next four days, we have to be a little bit patient, three days is probably not enough.

“By Sunday we may have a clearer sense depending on the size of testing.”

We will need tens of thousands of tests over the next days, he says, and we should start “masking up.”
This has slowed down the rate of new cases in the US, Rogers says.

“You have to choose your strategy and stick to it and a strategy of being free when the virus is eliminated, when there’s a new outbreak locking down that area, testing disproportionately and the country masking up, could mean this is relatively short-lived.”

Even relatively small numbers of daily cases are a cause for concern, he says.

“We don’t want to be finding 20 in one day, equally though Victoria and New South Wales took off at six to eight, or nine cases a day, so six to nine cases over a few days means we have a bit more of a problem.

“And 20 we have a real problem. This virus it starts at really low numbers, that’s the odd thing with all these outbreaks.