She said while the incubation period for COVID-19 is usually within 14 days, “people have developed the symptoms, more towards the one day period than the 14[days]”.
“It gives you very little time for the contact tracers, because you’ve got to get your cases diagnosed and then you’ve got to lock down those contacts,” Dr Chant said. “If you’ve got a sore throat today, don’t wait for two days to get it diagnosed. Work with us. Go get tested day one because every day you can give us allows us to to stop that spread.
“I am far from relaxed. This is a critical period for us and I need the co-operation of the public.”
Genome sequencing has confirmed the Sydney cluster is linked to Melbourne’s outbreaks in a clear sign the virus has seeded from Victoria, which recorded 238 new cases on Wednesday.
Virus detectives have identified patient zero from the Crossroads outbreak as a Melbourne freight worker who infected several colleagues at their workplace before they all attended a dinner party at the south-western Sydney pub.
NSW’s COVID-19 operations manager and epidemiologist Jennie Musto said the first clues were supplied via two simultaneous interviews of seemingly unconnected cases. A man in the Nepean told contact tracers he had been to the Crossroads Hotel, and a woman told tracers at Liverpool Hospital she had also had dinner at the venue.
“From there we’ve uncovered an additional 32 cases linked to the Crossroads Hotel and from there we have actually learned that the most likely link, supported by epidemiology, is that a man from Melbourne came into a workplace in Sydney and there was some transmission within that workplace and then they all went to a party the night of the 3rd of July at the Crossroads Hotel,” she said.
“So this is where it all began,” she said, with roughly six colleagues sharing a meal.
The man from Melbourne worked in the freight industry, but was not a truck driver.
“We didn’t think he was sick with COVID. He travelled on 30th of June. He’s been in NSW for a while and it wasn’t until we interviewed him and his colleagues with more details that we made the link that they were all at the Crossroads on 3rd of July,” Ms Musto said.
“We’ve identified all the links at this point in time, but we’ll get more cases and we’ll have to identify further links with them and further contacts and get them all to go into isolation as well,” she said.
Dr Chant said it was likely two or three people at the July 3 party were infectious.
She said the community cannot lose sight of the fact that COVID-19 was a “stealthy virus” that could be spreading throughout other parts of Sydney and NSW.
Premier Berejiklian said she was considering introducing further restrictions in NSW, but pursuing a strategy of elimination was “very unrealistic”.
“I think suppression is our only option,” she said, particularly when some residents continued to disregard public health orders and social distancing measures.
The Northern Territory has declared Greater Metropolitan Sydney a coronavirus hotspot. It means anyone from Sydney travelling to the NT must enter mandatory quarantine when its borders reopen on Friday.
Federal Deputy Chief Medical Officer Dr Nick Coatsworth said a strategy to eliminate coronavirus in Australia was not just unrealistic, “its dangerous”.
“True elimination is really only a realistic strategy when you have a vaccine,” Dr Coatsworth said, instead advocating Australia’s “aggressive suppression” scheme.
“The risk of elimination creates a false sense of security that may diminish the community engagement with widespread testing and lead to a downsizing of the enhanced public health response based on an assumption ‘we have got rid of the virus once and for all’,” he said.
Dr Chant urged the public to get tested if they develop any symptoms no matter their location, flagging a new testing target of more than 23,000 swabs per day.
In Sydney’s south-west alone, almost 3300 people came forward for testing in that 24-hour period.
NSW Health Minister Brad Hazzard supported the use of masks if people were in a public space where they could not maintain social distancing, stressing the importance of hand hygiene, and isolating if unwell.
“Complacency is the killer,” Mr Hazzard said. “I am really worried. We are still effectively in a war zone.”
In the 24 hours to 8pm on Tuesday there were 13 new cases, including 10 of those linked to Crossroads, taking the state’s total number of COVID-19 cases to 3328.
Of those 10 cases, six attended the Casula venue, two were close contacts of patrons and two acquired infection at the nearby Planet Fitness gym.
The remaining trio were returned travellers.
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Kate Aubusson is Health Editor of The Sydney Morning Herald.
Lisa Visentin is a state political reporter at The Sydney Morning Herald.