Victoria still has chance of containing coronavirus outbreak: epidemiologist

A graph shows how Victoria’s Covid cases are climbing at an alarming rate — but an expert says there is a reason to be hopeful.

Victoria is piling up local Covid-19 cases faster than NSW did in the beginning of its outbreak – but an epidemiologist has said Dan Andrews still has a better chance of turning things.

Victoria has recorded 1115 local cases in the 27 days since the state’s last “donut day”.

That includes the 76 new cases reported on Tuesday.

By comparison, NSW had recorded 767 cases by July 13, the 27th day of its outbreak, which started in mid-June.

That suggests Victoria may be headed for an even worse situation than NSW, which has by now accumulated more than 21,000 cases.

The purple line represents the cumulative number of coronavirus cases in Victoria’s current outbreak, while the blue represents NSW. Source: covid19data.com.au

But University of South Australia epidemiologist and biostatistician Adrian Esterman said Victoria still had a better chance of successfully tackling the Delta strain.

“I would be very wary about saying one state is doing worse or better than another, just by comparing case numbers at different time points,” he said.

“The best way of comparing these things is, does each state have this under control? The answer is no.”

Professor Esterman described the situation in Victoria as “borderline” and said it could go either way.

“There is still a chance they could bring it under control,” he said.

“The key thing there is their daily case numbers aren’t so big. Their contact tracers can handle it.”

An expert says Victorian Premier Daniel Andrews still has a chance to tamper down the virus spread. Picture: Andrew Henshaw

NSW, in the professor’s view, has “totally lost control”.

“Unfortunately the cases are going to keep going up and up and up, until eventually the effect of mass vaccination kicks in,” Professor Esterman said.

Epidemiologists tend to look at the “effective reproduction number” of the virus to predict how much it will spread.

That number is the amount of people that each infected person spreads the virus to, meaning if the so-called “Reff” is one, each person will spread it to just one other person on average.

Another 1164 local cases in NSW overnight, and sadly, another 3 deaths. The 5-day moving average is up to 1088, and the Reff is stable on 1.2. My prediction for today was 1182. If nothing else changes, 2000 cases a day should be expected by 10 September.

— Professor Adrian Esterman FACE (@profesterman) August 31, 2021

When the number drops below zero, the daily case numbers will decrease.

By Professor Esterman’s calculations, both Victoria and NSW had a reproduction number of 1.2 on Tuesday.

It’s a promising number that will avoid an explosion of cases, but the daily numbers will still increase exponentially, the professor predicted.

The alarming fact about exponential growth is that the bigger the number is, the more rapid the increase will be.

NSW Premier Gladys Berejiklian’s government has struggled to contain the spread of coronavirus since June. Picture: Jeremy Piper

While Victoria’s daily numbers remain low, its restrictions and vaccination drive – as well as luck – could favour the state and stop the figures from skyrocketing.

“A lot of it is luck, and a lot of it’s dependent on the city size, how much commuting there is – all these things come into play,” Professor Esterman said.

He strongly believes the early and hard lockdown in Victoria gave the state a fighting chance to contain the outbreak.

That’s despite the Victorian Premier’s “mistake” of taking the state out of its fifth lockdown “too soon”, setting the stage for the new outbreak in August.

University of South Australia epidemiologist and biostatistician Adrian Esterman.

“They really should have waited until there were zero cases a day,” he said.

The NSW decision to wait 10 days from the start of the outbreak to lock down Sydney robbed the state of any chance of containing the spread, Professor Esterman said.

“The NSW approach has epidemiologists like myself shaking our heads in despair,” he said.

“We’ve learned over many outbreaks in Australia that the way to tackle it – and especially with Delta – is to go in very, very fast, and very, very hard.

“You simply can’t control the Delta variant without going into lockdown, and everyone knows it. The only one who didn’t know it was Gladys Berejiklian.”