Coronavirus: ‘Mystery’ Victorian cases set a reopen challenge

Victoria’s 13 most recent coronavirus ‘mystery’ cases are spread across 12 different postcodes across Melbourne.

Victorian Chief Health Officer Brett Sutton in Melbourne on Monday. Picture: Andrew Henshaw

Victoria’s 13 most recent coronavirus “mystery” cases are spread across 12 different postcodes across Melbourne, highlighting the challenge the city faces in meeting the thresholds set by the Andrews government for the next stage of reopening.

From October 19, Melburnians are set to be released from stay-at-home restrictions — in place since July 7 — that currently see them confined to their homes and allowed to leave only for permitted work, medical care, essential shopping, exercise and public outdoor gatherings of up to five people from up to two households for up to two hours.

Under the Andrews government’s roadmap, this can happen only if Melbourne reaches a threshold of a 14-day daily average of fewer than five cases, with fewer than five cases with an unknown source in the fortnight.

On Monday, the first day of that fortnight, Melbourne’s 14-day daily average was 11.6 and eight new cases were reported.

A ninth case detected in the northern regional Victorian town of Shepparton was reclassified after being confirmed as a false positive.

There have been 13 unknown source or “mystery” cases in Melbourne in the most recent fortnight for which the statistic exists, which spans September 19 to October 2.

Concerningly, these are spread over Melbourne from the southwest and northwest to the southeast.

Chief Health Officer Brett Sutton said on Monday it was important for Victoria to meet the thresholds before reopening, with the mystery case threshold particularly important.

“The successful jurisdictions internationally and in Australia have gotten to five or fewer cases in a 14-day period when they’ve been able to maintain control into the long-term,” he said.

“Places that haven’t met that threshold have not been able to do that.”

Of the two most recent mystery cases, both from October 1, one is in postcode 3046, covering Glenroy, Hadfield and Oak Park in Melbourne’s northwest, while the other is from 3147, covering Ashburton and Ashwood in Melbourne’s southeast.

A single mystery case on September 30 was linked to Braybrook in Melbourne’s outer west, while another on October 29 was in a resident of postcode 3145, covering the affluent southeastern suburbs of Caulfield East and Malvern East.

On September 24, there were mystery cases linked to Donvale and Boronia, both in the east but more than 10km apart.

Three mystery cases the previous day were spread across the city, with one in postcode 3025, taking in Altona East and Altona North in Melbourne’s southwest, another in 3032, which includes Ascot Vale, Maribyrnong and Travancore in the inner northwest, and 3167, which is Oakleigh South in the southeastern suburbs.

There were also three mystery cases on September 22 — meaning that in just three days, there were eight cases for which contact tracers were unable to establish a source of infection.