Professor Mary-Louise McLaws questions whether essential workers are spreading Sydney’s Covid-19 outbreak

Sydney’s coronavirus outbreak could be better controlled if people were told one specific detail about the new cases, an expert says.

One of the country’s leading epidemiologists says crucial information is missing when NSW’s daily Covid-19 case numbers are announced that could help paint a clearer picture of how the virus is spreading.

Professor Mary-Louise McLaws, from the University of NSW, said Sydney’s escalating outbreak was being driven by a rising trend of people who are infectious in the community.

Professor McLaws questioned why NSW Health was not providing full details on why these people were leaving their homes as it could help others evaluate their own behaviour, suggesting much of the spread could be coming from essential workers.

Epidemiologist Mary-Louise McLaws says we need to know more about the people infected with Covid-19. Picture: Justin Lloyd

“What the government is not telling us, which they need to, is how many of those not in isolation were essential services workers who inadvertently acquired it at work and then took it home to their household and caused ‘x’ number of people in their households to be infected,” she said.

“So we have an idea of the link between essential services getting infected, taking it home and having people get it at home.

“We need to really learn more context so that we can actually learn from it.

“For example, if they are essential services workers, why aren’t they being tested at the workplace?”

Premier Gladys Berejiklian has defended calls that the government should have locked down sooner. Picture: NCA NewsWire/Jeremy Piper

The government has been criticised for its lack of definition on what constitutes an essential worker and has moved to stop people leaving their local government zones for work in areas of most concern.

Under the public health orders, authorised workers can be employed in a range of fields, including health, teaching, retail, trades, media and hospitality.

Several workplaces have been identified as transmission sites, including a KFC in southwest Sydney where 12 staff members caught the virus.

Of the 345 new coronavirus cases announced on Thursday, 229 of them were in the community at some point in their infectious period.

Professor McLaws said rapid antigen tests could be used at workplaces to catch positive cases at their earliest contagious stage and divert people away from their homes to stop household spread.

She asked whether there needed to be more intervention or advice in workplaces to ensure staff are operating safely, right down to how the toilets are used and if windows are left open.

Police patrol in the Sydney suburb of Strathfield after it became a new area of concern on Thursday. Picture: NCA NewsWire / Christian Gilles

“Because if it’s not socialising … if you don’t think that’s happening, and most of it’s household, how are the households being seeded? By somebody that they are all locked down with,” Professor McLaws said.

“What they (the government) can easily do in the morning … they could tell us, ‘There were 50 at work, another 50 we don’t know yet, another 50 that were socialising or had a social aspect of work, such as car pooling’.

“Without the granulation of information, we’re not going to be able to cut the infection transmission cycle.”

That lack of transparency made it hard for people to know what they could do the help stop the virus, Professor McLaws said.

“An outbreak isn’t fixed by authorities alone, it’s a partnership,” she said.

NSW is breaking testing records during the latest outbreak. Picture: NCA Newswire /Gaye Gerard

She also responded to comments from NSW Police Minister David Elliott, who on Wednesday claimed rocketing community transmission could be traced back to Sydney’s “freedom rally” protest on July 24.

Mr Elliott said it was “too much of a coincidence” for NSW to have posted record transmission numbers in the weeks following the illegal protest attended by thousands of people.

“I have no doubt two weeks ago that protest is probably the reason why a lot of these numbers in southwestern Sydney continue to rise,” he told Sky News Australia.

Despite stressing she was extremely disappointed with the protest, Professor McLaws said it was a “big call” to link the event to rising case numbers without further evidence.

Police and Emergency Services Minister David Elliott blamed high case numbers on an illegal protest in Sydney. Picture: NCA NewsWire/Bianca De Marchi

She also criticised the government for not locking down Sydney sooner, saying there was ample warning from Delta outbreaks overseas.

Professor McLaws said the decision was “certainly not based on their own excellent observation” that the strain was a danger, adding that relying on contact tracers was “foolhardy”.

“It was really very obvious, from overseas experience, that Delta spreads rapidly,” Professor McLaws said.

“They (the government) were even telling us, with their words of anxiety, that this was something to be fearful of … in that first week, and yet we didn’t lock down until we had 54 cases.

“That was far too slow when they knew they were dealing with a highly infectious agent that we’d never seen be as infectious ever before.”

Her comments came after Premier Gladys Berejiklian, Health Minister Brad Hazzard and chief health officer Kerry Chant this week all defended the call not to lock down earlier.