“We need to be cautious. We should not over-react, but also be prepared to respond if this is an early sign of re-establishment of transmission.”
The spike is being driven by outbreaks in Victoria.Credit:James Brickwood
Active cases are calculated by taking total case numbers and deducting recovered cases and deaths. There were 2306 active cases of COVID-19 on April 19 but the numbers tumbled every week as recovered cases outnumbered new ones.
The downward trend ended last Sunday at a low of 380. Active cases nationwide rose to 382 on Monday, 389 on Tuesday, 398 on Wednesday, 412 on Thursday, according to figures compiled by the federal government at 4pm each day.
Peter Collignon, an infectious diseases physician and a professor at the Australian National University, said the trend was a concern and showed eradication was unlikely.
“Most of the active cases are returned travellers, but the ones that worry me are the ones where there is not an obvious association – they’re in the community,” Professor Collignon said.
“Winter increases the risk of viral transmission so in some ways I’m not surprised it’s gone up.
“Do I think it’s a concern? Yes. Do I think it means we’ve lost control? No. Do I think we will lose control? No.
“But this shows why we need to keep our guard up and why we need to do more testing.”
The number of active cases in NSW has been relatively steady over the past week. It rose from 308 on Saturday to 314 on Sunday and has ranged from 317 to 319 in the days since.
Victoria has seen a significant increase, however, with active cases reaching a low of 44 on Sunday and rising to 83 on Thursday.
Victoria will proceed with its plans to ease social restrictions on Monday, but Victorian Deputy Chief Health Officer Annaliese van Diemen warned of more cases to come.
“It’s the cases that we don’t have known links to that are the biggest concern for us, and there are fewer of those today than there were yesterday, so that’s a good sign,” she said on Friday.
“At the moment we expect there to be secondary cases when there are household contacts involved, so that’s not unexpected.”
Victoria has recorded 52 cases in the past three days, including eight people infected through untraceable community transmission whose cases emerged on Thursday.
University of Melbourne professor of epidemiology Tony Blakely said the biggest concern in the weeks ahead could be the use of public transport as workplaces opened up.
“There is a good chance we may need to tighten up physical distancing at some point,” he said.
“On the other hand, modelling we have done suggests that there is still a chance the rates can go down and everything will be okay – it is really hard to predict.
“My bet, though, is that the rates will probably go up if we continue to open up – unfortunately.”
Professor Blakely said it was too soon to tell whether the Black Lives Matter protests or other changes were a factor, while Professor McCaw said the potential for increases had always been understood.
“The protests of recent weeks have resulted in some [to date isolated] cases and at this stage are not identified as a driver of the increased Victorian activity,” said Professor McCaw.
“Whatever the consequences of the Victorian notifications the past few days, this re-enforces that the pandemic is still active, and we are most certainly not in a post COVID-19 world.
“We remain almost completely susceptible and the virus continues to circulate. We must maintain physical distancing and hygiene practices.
“Indeed, as we are out and about more, the need to keep at least 1.5 metres apart and practice good hygiene is more important now than at any time since we first went into lockdown.”
David Crowe is chief political correspondent for The Sydney Morning Herald and The Age.
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