Why can’t ‘gold standard’ NSW get its cases down, despite weeks in lockdown?

Gladys Berejiklian warned her state early on that case numbers will "bounce around".

Gladys Berejiklian warned her state early on that case numbers will "bounce around". Photo: Getty

COVID-19 case numbers in New South Wales are still rising even as Greater Sydney faces a fifth week in lockdown, with epidemiologists suggesting essential workers in supermarkets be prioritised for vaccines or start wearing face shields and goggles.

Despite heavy restrictions and a city-wide lockdown, cases have stubbornly stayed above 110 every day for a week.

Experts say the fast-spreading Delta strain presents huge challenges to contact tracers, who may struggle to reach asymptomatic people before they become infectious and spread the virus.

“Rising cases don’t necessarily mean all is lost,” said Professor Alexandra Martiniuk, an epidemiologist at the University of Sydney.

“Lockdown is working, but infectious cases in the community is not good and things can certainly be improved.”

Essential workers push NSW case numbers

NSW Premier Gladys Berejiklian warned from the start of the lockdown that case numbers would “bounce around”.

Two weeks ago, numbers pinballed from 50 to 112 then back to 65, before hitting 111 on July 17.

Now, the bouncing has largely stopped – since that day, NSW has only recorded two days below 100, its seven-day average now at 128.

sydney lockdown

Cases in Sydney are rising, despite more than a month in lockdown. Photo: AAP

Restrictions have tightened gradually to close construction, mandate tighter work-from-home rules, and stricter shopping rules.

State premiers including Daniel Andrews and Mark McGowan have demanded NSW clamp down even further.

USYD research found compliance with lockdown rules in NSW was as low as 40 per cent earlier in July.

However, NSW officials said spread is predominantly occurring in ‘essential’ workplaces and industries that couldn’t be shut, like supermarkets or transport.

Many cases also came from extended family groups ‘mingling’ across households.

Chief health officer Kerry Chant said that was why so many cases were concentrated in Sydney’s south-west and west.

Of 145 cases on Monday, at least 104 were from those areas alone, with only 38 across the whole rest of the city.

Dr Chant said people in Sydney’s west “keep our city running”.

“They do a lot of the work in distribution centres, food, logistics, transport,” she said.

For this reason, NSW will reportedly prioritise supermarket workers for vaccinations.

The latest set of exposure sites in western Sydney mostly included banks, supermarkets and pharmacies, alongside the fast food and cafes that have been allowed to remain open.

Professor Martiniuk said Sydney retail should offer wider ‘click and collect’ options to discourage in-store browsing, but said more support was also needed for essential workers.

She noted Delta “rips through households”, citing cases of inter-household transmission as grandparents care for children so parents can attend work.

“We can assist with funding supports, or child care or senior care options,” Professor Martiniuk told The New Daily.

Social advocates have pleaded for more income supplements for those on welfare, who miss out on current disaster payments, so people aren’t forced to leave home to find more work.

Outbreak not ‘uncontrolled’

Professor Peter Collignon, Australian National University infectious disease expert, told TND there was a case for getting essential workers to the front of vaccine queues.

In the meantime, he recommended workers wear goggles and face shields, as well as masks.

“What other restrictions would you have? Essential workers need to move around. A curfew? I can’t see it will make much difference, if the main problem is workers spreading to their families,” Professor Collignon said.

Professor Collignon said while cases were still rising, it wasn’t “exponentially”.

That, he said, was a sign lockdown was working – albeit slowly.

Sydney in coronavirus lockdown

Essential workers are still needed to keep the city ticking over – and these workplaces are areas of transmission concern. Photo: AAP

“If you had uncontrolled spread, you’d expect doubling every five days. What they’ve done had an effect, but it’ll be the same speed going down,” he said.

“It takes a while for it to go down. Look at Melbourne last year. Having harsh restrictions doesn’t mean it’ll be better in a week.”

During Victoria’s second wave of lockdowns, the state logged 700 cases on August 5.

That was a month after the state government enacted ‘Stage 3’ lockdown measures in early July, and after ‘Stage 4’ began in early August.

Delta ‘challenges’ contact tracing reliance

NSW has relied heavily on its muscular contact tracing system – described as “gold standard” by Ms Berejiklian – to avoid previous lockdowns.

But as Professor Collignon noted, Delta made people sicker, faster, which slashed the time contact tracers had to find cases and get them to isolate.

Dr Chant said many cases were being diagnosed with no symptoms, despite being infectious.

Despite case numbers plateauing in recent days, larger numbers of cases had been active in the community for part or all of their infectious period, suggesting they hadn’t been reached by contact tracers.

Dr Chant has repeatedly denied contact tracers are “overwhelmed”, but Professor Collignon said Delta’s speed presented “challenges” to tracing systems.

“Delta is twice as infectious as the original Wuhan variant. People seem to be infectious earlier, and more infectious when asymptomatic,” he said.

“That makes it harder for contact tracers … when you have more than 20 or 30 cases a day, there’s a lot of places people have been. Contact tracing starts becoming difficult.”

Professor Martiniuk echoed this, saying the numbers infectious in the community was “a concern” made “more difficult” by Delta.

She suggested further boosting NSW’s contact tracing team, and called for researchers to have more data about the cases in the community, to understand who they were; for instance, whether casual contacts of a known case, or people not complying with health directions.

“Increasing testing capacity and speed might be able to help reduce the number of positive COVID cases in the community and/or the length of time they are infectious in the community,” she suggested.

“Home testing or workplace testing might be useful.”

Professor Mike Toole, epidemiologist with the Burnet Institute, said it could take as little as four days for someone to catch and become infectious with Delta – days faster than the original strain.

At some point, he suggested, there would be a “critical mass” of cases, that would make contact tracing too hard.

“You’ve got to get them in that four-day period, so they’re not in the community for days,” Professor Toole told TND.

“Contact tracers are human. They’re very good, but they’re human.”

Burnet modelling suggested Sydney’s current restrictions would see cases remain above 40 per day for weeks, but tougher measures like those seen in Melbourne’s lockdowns – like strict travel distance limits and outdoor masks – could quickly force down case numbers.

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