At Saturday’s coronavirus briefing in Victoria, Premier Daniel Andrews stressed his “growing concern” over the rise in cases where authorities could not figure out how someone had caught the virus.
Classified by Victorian health authorities as “community transmission”, they are cases where, despite the efforts of contact tracing teams over several days, or sometimes weeks, they can not trace the infection back to the “index case” or original source.
Mr Andrews said 49 more such “mystery” cases had been added to the community transmission tally in the past day.
“Forty-nine doesn’t necessarily seem such a large number but 49 mysteries when it could be much more than that because you can’t find who that original case was, that is a significant concern to us,” he said.
Of the 10,931 coronavirus cases recorded in Victoria since the pandemic began, 1,841 — about 17 per cent — have so far been classified as community transmission.
And 49 isn’t even the biggest increase this week.
On Wednesday, the Department of Health and Human Services (DHHS) afternoon update stated the number of probable community transmission cases was 1,418.
The next day, that had risen to 1,698, a jump of 280 cases, which suggested a large number of contact tracing investigations had been closed with the source of infection unknown.
And the number of cases classified as community transmission jumped by nearly 100 between Thursday and Friday.
Mr Andrews said one of the reasons these cases mattered so much was because when the infection couldn’t be traced, it left open the possibility that somewhere, someone was unwittingly spreading the virus.
“That can mean there are many more than 49 out there that have very mild symptoms or no symptoms at all, they can be at the height of their infectivity, and be infecting other people unbeknownst to them,” he said.
“That is the real challenge here. It is a silent enemy, it is a very cunning enemy as well.”
It could be the main reason restrictions are tightened
And it’s one of the reasons why the Government looks set to introduce further restrictions in Victoria beyond the six-week lockdown in Melbourne and the restrictions on visitors across the Geelong and Colac region.
Health experts have been poring over the state’s coronavirus data, looking at population demographics to pinpoint where transmission needs to be driven down, in addition to already identified workplaces such as aged care homes, abattoirs and healthcare settings.
On Friday, Chief Health Officer Brett Sutton acknowledged that tighter restrictions would create their own public health harm as they hit mental health, employment and businesses.
“These are impossible decisions in a number of ways,” he said.
But on Saturday, Mr Andrews was clear: “Numbers are too high and there is a growing case for us to do more.”