Fly-in, fly-out workers are being discouraged from travelling outside of Perth with the state government asking mining companies to consider extending the swings of staff already on site.
Genomic sequencing confirmed Case 1022 – the returned woman from Sydney – had contracted the virus while having brunch at a Bondi cafe on June 19 with her husband and son.
The physiotherapist was tested upon her return to Perth on June 20 and returned a negative result, permitting her to move freely in the community.
Health authorities suspect the woman, aged in her 50s and from Mindarie, was infectious for three days in the community between June 22 and June 25 before the cafe she visited was listed as an exposure site and she again got tested, returning a positive result on Sunday.
Mr Cook said the woman, who is partly vaccinated, had done everything right as contact tracers scrambled to test her more than 1000 casual contacts – two of which have already tested positive.
“The next few days will be crucial for Perth and the rest of the west,” he said.
“Keep yourself informed, particularly if you are from the northern suburbs please check out the exposure sites to know whether you should be tested.”
WA Chief Health Officer Andy Robertson said it was a positive sign the partners of each of the cases had tested negative, leading him to believe contact tracers were identifying potential cases before they became infectious.
The initial case’s husband had also received his first COVID-19 vaccination.
“Part of the lockdown is to identify these cases quickly and lock them down. We may still get further cases in quarantine but we are not as concerned about those cases,” Dr Robertson said.
Around half of the infected trio’s close contacts had so far returned negative test results, representing 109 people.
Of a further 1828 identified casual contacts, so far 275 have returned negative tests. On Tuesday, the list of potential exposure sites grew to more than 25 venues.
Mr McGowan said whether the lockdown needed to be extended would be determined later in the week, with more than 14,000 people tested on Monday.
“I note [the lockdown] is very, very disappointing, but we can take comfort in the fact that we have acted quickly,” he said on Monday night.
“Sydney is now going through a two week, probably more, lockdown, we’re hopeful a four day lockdown and all the measures we’re putting in place will be enough to crush and kill the virus in its tracks.
“We’ve done it before … and now it is time to do it again, a time to prove to the rest of Australia and to the world what can be achieved when a community comes together.”