It all began with roughly six colleagues sharing a meal...
Virus detectives have concluded that a Melbourne freight worker, who travelled to NSW on June 30, passed the virus to a number of colleagues during a visit to their Sydney office. The group then went to a dinner party at Casula's Crossroads Hotel on the night of July 3.
It's believed two to three of the people at the party were infectious.
NSW chief coronavirus detective, Jennie Musto, said that the man didn't think he was particularly unwell.
"[He] didn’t think he was sick with COVID. He travelled on the 30th of June — he’s been in NSW for a while," she told reporters yesterday.
"And it wasn’t until we interviewed him and his colleagues with more detail that we made the link that they were all at the Crossroads on the 3rd of July."
Speaking to the media this morning, NSW Chief Health Officer Dr Kerry Chant said now "around 40" confirmed COVID-19 cases have so far been linked to the party.
It's a sadly familiar story.
We are urging anyone who visited the Crossroads Hotel, Casula from July 3 to July 10 to come forward for testing & self-isolate for 14 days. The next 2-4 weeks are critical for NSW. pic.twitter.com/2ODU47haxE— Gladys Berejiklian (@GladysB) July 12, 2020
Throughout the pandemic, there has been a number of events in which one or a few individuals have been responsible for a disproportionately large number of infections.
In South Korea, roughly 40 people who attended a single church service were infected with COVID-19 at the same time; at least 52 people tested positive after attending a choir practice in the US state of Washington; and 71 people were infected in an apartment building in China after an asymptomatic woman returned from the US and used the communal lift.
Here in Australia, a wedding in the NSW coastal suburb of Stanwell Tops in March saw 35 guests infected by a group that had recently arrived from the US. And of course, there was the Newmarch House aged-care home outbreak, in which the diagnoses of 34 colleagues and 37 residents were traced to a single staff member. Tragically, 19 of those residents passed away.
The source of these cases is known as 'super spreaders'.
Super spreaders aren't unique to COVID-19. Some researchers estimate that, in any given outbreak, 20 per cent of the population is usually responsible for causing over 80 per cent of all infections.
Which is precisely why identifying them and their contacts — and doing it quickly — is crucial to halting the spread of the disease.