'A wicked enemy': why Australia's second wave of coronavirus will be tougher to fight

On Friday 10 July the health department of New South Wales revealed 14 new cases of Covid-19 in the state – 13 of which were linked to returned international travellers in hotel quarantine. The numbers did not seem overly concerning, but as we now know small numbers can become big numbers very quickly.

Seven days later New South Wales premier Gladys Berejiklian announced restrictions would be reimplemented across the state as eight new cases of Covid-19 cases were recorded – just two of them returned travellers in hotel quarantine.

By then a cluster of 42 infections had emerged linked to the Crossroads Hotel in south-western Sydney.

Across the border, Victoria reported another record day of new cases: 428 people diagnosed in the previous 24 hours, along with three more deaths. Only a month earlier, the state had reported 21 new cases – 15 of them returned travellers in quarantine.

Related: Most Covid-19 patients admitted to a Sydney hospital in March still have symptoms

‘So wildly infectious’

“This is a wicked enemy,” the Victorian premier, Daniel Andrews, said on Tuesday, clearly exhausted by the second wave he was trying to manage as case numbers held fast in the triple digits.

“It is so wildly infectious. It moves so fast. It’s cunning in some respects where people can be infectious for quite some time and not know it – not have symptoms or, if they have symptoms, they’re so mild.”

Questions were asked about whether Victorians, most of them by now under stage three lockdown, needed even harsher restrictions implemented to curb the spread.

The speed with which Victoria and New South Wales have found themselves once again facing restrictions has led some to ponder whether this second wave was a new, more infectious strain. But experts say while there is no evidence of that, the population in which it is currently spreading means it will be much harder to contain the second time around.

“There is no evidence at all of a new more virulent strain,” said Prof Lyn Gilbert, who leads the expert infection control group advising the Australian Health Protection Principal Committee [AHPPC]. “In fact, some people have been suggesting that it’s less virulent because the case fatality rate is going down. However, there is no evidence of any significant change in virulence.”

The key difference was the situation, Gilbert said.

“In the first wave that began around March, more than two thirds of cases – up to 80% – were from returning overseas travellers and their contacts,” she said. “Generally speaking, these are well-off people living in larger houses with higher socioeconomic situations. Once that was recognised, and borders closed and hotel quarantine put in place, that was able to be controlled more readily.

“But with this situation that unfolded in Melbourne, there was a leak from hotel quarantine due to security staff not maintaining infection control measures. It then went from those staff to families and to the community and it obviously became widespread before it was recognised.”

In other words, it was the delay in detecting the cases that partially sparked the latest outbreak.

Returning travellers can be immediately identified, quarantined and tested. But the lag between security staff being infected and their contacts being identified provided opportunity for spread: into homes, into apartment towers, and throughout the community.

“It makes it harder to contain, there’s no doubt about it,” Gilbert said.

It also means that with the second wave, there is increased chance of picking up the virus in the community, and contact tracing is much more difficult.

‘It’s Australia’s problem’

In a quarantine hotel or on a cruise ship at sea, the spread and tracing can at least largely be contained to the people there. But at a pub like the Crossroads Hotel – a large venue where there is a mix of community members and interstate travellers stopping in on their way to cross the borders – the risk of spread beyond the immediate environment is high. And the time lag between recognising a cluster and alerting those impacted that they need to isolate and get tested means that visits to shopping centres, gyms, and family may have occurred in the meantime.

The Crossroads, 35km south-west of Sydney’s city, is in the Liverpool city council area and the city’s mayor, Wendy Waller, said 25% of the population are over the age of 55. “We have a high migrant population, and among the highest intakes of refugees,” she said. “So there are a lot of issues to consider when we are asked to stay home and last time, we rose to the challenge. This time people are doing the same, they are being conscientious, they are following the health rules and many people are getting tested.”

Was she concerned containment measures were too slow to be implemented in Victoria, given the virus had spread into her area from there?

“The virus is from Victoria, but it’s not Victoria’s problem,” she said. “It’s Australia’s problem, it’s the whole of the nation, it’s not about just us, or Victoria.”

Gilbert said she felt “a bit burned out and disappointed” that this new outbreak had occurred, but that she was “not entirely surprised”. However, she was frustrated with the blame game that was going on, she said.

“I sometimes get frustrated with the plethora of experts who criticise health authorities, and there is some criticism of AHPPC,” she said. “But it is so difficult for someone not working on it to understand the complexities. And it is complex. There are a lot of forces pushing this way and that. Coming up with the right decisions with AHPPC and with health and economic and employment and restriction burnout – all those factors having to be considered [and] it means making decisions can be very difficult and stressful.

“I’m a small player in it this, but I can say the state and territory chief health officers and politicians are all under enormous pressure. I know how burned out they are feeling. They’re not admitting to it, but they’re burned out, and they’re working nonstop, and they’re doing their very best.”

‘Much worse than the first wave’

The head of the infectious diseases department at St Vincent’s hospital, Associate Prof Gail Matthews, said the public should be reassured that while during the first wave, “nobody knew anything,” experts including public health officers, clinicians and policy makers were somewhat more prepared for whatever is to come this time around.

“I think we all feel if we do have a second wave or a big outbreak or whatever you want to call it coming again, now, we are so much more prepared than we were in March, April,” she said.

She said an important aspect of the second wave was the environments where clusters were being identified.

“The more people are within an environment, the more chance you have of having more significant spread, obviously,” Matthew said. “So the bigger the venue, the more concerning it is, even if you just get one person in there who’s a super spreader or who is highly infectious.

Related: Victoria and Melbourne coronavirus map: where Covid-19 cases are rising or falling

“That’s why the advice has gone back to limiting the number of people in venues partly so that you limit the potential for numbers of people to be infected for one infected person coming in. But also it becomes easier to contact trace as venue numbers are reduced, which is really important if you’re going to then limit the transmission.”

Given the difference in spread, containment would be more difficult this time around, a professor of infectious disease and physician at the Canberra hospital, Peter Collignon, said.

“It’s much worse than the first wave to control because it’s pretty much all community transmission,” he said. “But, at least we still know how it spreads. Though it will take a while this time to suppress it to low numbers and it makes elimination very unlikely, we can’t throw up our hands in horror. We need to see what’s happening early next week. With any intervention like lockdown it will take at least 10 days to two weeks to start seeing an effect.”

Despite the virus being harder to stop now, one thing had not changed, Collignon said: the methods of containing it.

“This is largely spread by droplets,” he said. “That means if you keep basic precautions in place – physical distancing of 1.5 metres from others, you wash your hands, you stay at home when even mildly sick and also get tested, and you avoid getting together in groups especially inside, you can contain it. The basics of what stops it spreading hasn’t changed.”