As Sydney approaches four weeks in lockdown, the number of Covid cases infectious in the community – which experts say needs to reach close to zero before restrictions can be eased – remains stubbornly high.
On Thursday, 124 new local cases were announced in NSW, and up to 80 of those were active in the community for all or part of their infectious period. The day prior, 110 new local infections were announced, 60 of which were active in the community for part or all of their infectious period.
“It’s a key number that we are very keen to bring down, and a key indicator of risk to the community at any one time, so it’s an important number,” Dr Jeremy McAnulty, the executive director of NSW Health’s Covid-19 public health response branch, says.
McAnulty told Guardian Australia that while most people were getting tested as soon as they experienced symptoms, others were waiting too long in the hope that the symptoms may pass and may not be Covid-related. Aged care homes, construction sites, and supermarkets are all locations people are visiting while infectious, he says.
The infectious period for Covid-19 is 14 days – calculated from two days before the onset of symptoms, or, if someone has no symptoms, from two days before they tested positive.
“So those two days before onset, they’ve probably been doing what they’ve been allowed to do in lockdown: shopping for essential goods and going out for essential work,” McAnulty says.
Guardian Australia asked for a breakdown of types of locations being visited while infectious, and while McAnulty did not have this information, he says “in general, we’ve had transmission in some supermarkets, we have had transmission in workplaces, we have had transmission in families, and we have had transmission at aged care facilities, and we have also had transmission at construction sites in previous days”.
McAnulty says the majority of those infectious in the community were not vaccinated. He adds that most people were doing the right thing, and that those who broke restrictions were, for most the part, not doing so deliberately or maliciously.
“I think there’s so many messages that people have to follow, it’s sometimes easy to get lost in it all,” he says. “But one of the key messages is, even though we’re in lockdown, even though you are allowed to go out to work, or to the supermarket, or to exercise, then in all those instances, just assume either you or the person you might be interacting with has Covid and therefore act accordingly.”
“So keep your distance, wear a mask, stay at least one-and-a-half metres away from them. I’ve noticed maybe people have seemed to have forgotten those key messages that we have been pushing for so long.”
On Thursday the NSW premier Gladys Berejiklian said during the daily press conference: “Unfortunately we get recurring cases of people who have symptoms and turn up to work thinking they’re not infectious … then we have people who think they have no symptoms and visit people outside their household and spread it.”
Asked whether it would be helpful for people to have more clearly defined rules around measures such as mask-wearing, such as a similar mandate to Victoria where masks need to be worn outside the home at all times, including outdoors, McAnulty says: “In my observation and through talking to people, I don’t think mask-wearing is the issue.”
“We know that transmission is very much less likely outdoors, and indoor transmission is much higher,” he said.
But a professor of public health and adviser to the World Health Organization (WHO), Mary-Louise McLaws, says NSW needs clearer and tighter mask-wearing rules that “remove the luxury of interpretation” and take into account Delta spreads more easily, as seen at outdoor sporting events in Victoria.
“We’ve had five deaths with this Delta outbreak in New South Wales now, and over 1,653 cases,” she says.
“We have a duty of care not just to ourselves but everyone around us. People just aren’t getting it and I don’t blame them. Because they think if they’re outdoors they’re OK and don’t have to wear a mask. The rules aren’t well explained including why they are being asked to put a mask on.”
McLaws says masks are not the key measure, but given this strain is more infectious than any other, it makes sense to use every tool at the disposal of NSW residents.
“I’d be just saying even if you pass someone for a fleeting moment, wear a mask, even outdoors, even at a greater distance than 1.5m.”
Asked what proportion of people who were in the community during their infectious period were symptomatic, McAnulty says that “broadly, most people are symptomatic”.
“It’s understandable human nature, people don’t want to … it’s an inconvenience to get tested,” he said. He agreed some people delayed getting tested hoping their symptoms would pass.
“We want people to act very differently during this pandemic,” he said. “Normally, we say, if you have got a cold, you know, you don’t need to go and see a doctor. But let’s completely turn that message on its head during the pandemic, we absolutely want you to go get tested with even the mildest of symptoms. So don’t hesitate. And don’t be embarrassed to turn up for testing several times.
“But it’s human nature, people don’t want to bother other people.”
Pressed on why Victoria has managed to get the proportion of cases infectious in the community down while NSW was struggling, McAnulty says: “I don’t know Melbourne as well, but I think it’s the nature of how many cases and contacts we have, and we just need to work through these, find the cases early and get those key messages out to the community”.
He is hopeful the impact of the lockdown will start to be reflected through lower case numbers in coming days, so long as people adhere to public health measures.
“We are working around the clock,” he says. “These measures worked last year. This year, we’ve almost got a new virus, it’s so infectious. It’s easily transmitted in families, in workplaces. It’s just so much harder to contain. So it will take a while to see numbers come down. We put in the laws, but if people understand, and comply with those rules, which are really tough and inconvenient, we can crush this thing.”
Vaccinations urgently needed for all essential workers
A professor of epidemiology with the University of Sydney, Alexandra Martinuik, says thoroughly understanding where people are in the community while infectious and why they are there is crucial in determining whether current restrictions are enough to control the outbreak.
“We really could use greater detail on this from NSW Health,” Martinuik, who is also an honorary senior research fellow with the George Institute for Global Health, says.
“It would need to be anonymous data obviously, but at least it would provide greater detail. Are they casual contacts of a known case? Are they close contacts not isolating well, and if so, what do they need to isolate well? Have they had a previous negative test and how many days prior?”
Martinuik says the public also needs more detail on why people had not sought a test sooner if they had symptoms while out in the community.
“If the person has symptoms what are the reasons they have not yet sought a test?” she says. “Do vaccinated individuals need to be more alert to the potential they are positive and might not have symptoms?
“Increasing testing capacity and speed might also be able to help reduce the number of positive Covid cases in the community and the length of time they are infectious in the community. Home testing, or workplace testing, might be useful in these times.”
Understanding where people are spreading the virus in the community might lead to authorities placing greater emphasis on services like click-and-collect from groceries and pharmacists, she says.
“We may need to improve ventilation in these settings, and proper mask wearing can improve, with some people wearing them under their nose. I’ve heard of people ‘swinging through the grocery shop’ for their last few dinner items every day, or grocery shopping as something to do, so they are going daily. This of course increases interactions and risk for all, and people should ideally shop as infrequently as they can manage.”
McLaws agreed with Martinuik that more granular information was needed about the most problematic areas of infection in the community. “And sadly we may have to move to a system of curfews for this variant if we can’t understand how and where people are catching and spreading this in the community,” McLaws says.
She says supermarket workers, service station workers, and chemist workers should be priority groups for vaccination given health authorities said people were in these setting while infectious.
“Those workers should be able to get tested regularly and vaccinated as priority groups, and those vaccines and tests should be brought to and administered at their workplaces to make it easier for them,” she says.