Will Sydney’s Covid lockdown work and how different are restrictions to Melbourne’s ‘ring of steel’?

Greater Sydney’s lockdown has already been extended by another four weeks but New South Wales health authorities are facing questions about what more can be done to limit the spread of Covid-19, as well as criticism from other states.

A new daily record of 239 cases was announced on Thursday, along with tightened restrictions targeted at eight local government areas (LGAs) – Fairfield, Canterbury-Bankstown, 利物浦, Cumberland, Blacktown, Parramatta, Campbelltown and Georges River.

Masks must be worn outdoors in these areas and a 5km travel limit has been established, in addition to existing restrictions and testing requirements that are stricter than rules for the rest of the city.

Despite this, premiers from other states have criticised the lockdown settings in place in 悉尼 for being less strict than the stage-four restrictions introduced at the peak of Melbourne’s second-wave lockdown last year.

The Victorian leader 丹尼尔·安德鲁斯 last week called for a “ring of steel” to be put up around Sydney, something he claims to have enforced last year to limit Covid spreading out of Melbourne.

NSW health authorities have acknowledged the majority of new transmissions are among essential workers, their households and those visiting family in other homes, but details of the types of workplaces where transmission is occurring have not been made public.

新南威尔士州州长 Gladys Berejiklian has stared down calls to introduce measures including the curfew that was introduced in Melbourne, citing a lack of health advice to support the restriction.

Expert opinion is split on whether adopting Melbourne’s stage-four rules such as a city-wide outdoor face masks mandate and curfews would work to limit Covid spread in Sydney, or whether its geography, demographics and the infectiousness of the Delta variant would blunt the benefit of some measures.

However it is broadly agreed that for case numbers to slow and the outbreak to end, movement across Sydney has to further decrease from current levels – at least until millions more doses of vaccine are administered.

So just how different is Sydney’s lockdown compared to the peak of Melbourne’s stage-four restrictions? And what do experts think will work in Sydney?

Sydney’s lockdown has been progressively strengthened since it was first introduced in late June, with current rules limiting reasons for leaving home.

For most of Sydney, residents are allowed to leave their home to exercise with one other person from a different household, but there is no limit on members of the same household exercising together.

These residents cannot travel more than 10km, with the same distance limit also applying to shopping for essentials.

Tighter restrictions were in place during stage-four restrictions in Melbourne this year, with residents only allowed to shop or exercise within 5km of their home. Exercising was permitted only in groups of two, regardless of whether they were from the same household.

A curfew was also imposed for Melbourne residents between 8pm and 5am, and face masks were mandatory for all indoor and outdoor settings. Masks do not currently need to be worn outdoors in most of Sydney.

然而, under targeted restrictions in place for the eight LGAs of most concern in Sydney, movement rules are stricter than Melbourne’s stage-four lockdown in some ways, with residents unable to leave their locality to exercise or shop unless they are an essential worker.

For these residents, masks must now be worn whenever residents or workers in these LGAs leave their home, even outdoors, and their travel distance has been shrunk to 5km from home.

Michael Toole, professor of international health at the Burnet Institute in Melbourne, has studied Melbourne’s stage-four lockdown in detail and has been modelling the progression of Sydney’s current outbreak.

While a handful of rules have been tightened since his modelling was formed, Toole stands by a prediction that under Sydney’s current lockdown settings, [object Window] could take months, potentially until the end of the year, for case numbers to get closer to zero.

He acknowledged that without the current lockdown, cases would likely be in the thousands, but that more needs to be done to reduce the virus reproduction rate to below one – meaning it is lowering overall.

He points to a current reproduction rate of lower than one (R0.8) in south-west Sydney as proof that tighter measures are needed, but believes “Sydney can’t keep playing whack a mole”.

“It might be looking successful in south-west Sydney but now they’re behind the curve in western Sydney, and the rest of Sydney really,“ 他说, noting the reproduction rate in these areas was now above one.

Toole is sceptical of the commonly raised claim in NSW that no transmissions have been recorded outdoors (he notes transmission of Delta at the Melbourne Cricket Ground this month) and believes that even if none have, outdoor masks should now be implemented across the city.

He said it was difficult to know which measures of Melbourne’s stage-four rules worked and which were less effective, so was cautious of ruling out the efficacy of a curfew in Sydney.

“With Delta the horse boltsthey should be using everything in the toolkit,” Toole said.

Not all experts share Toole’s view.

Prof Peter Collignon, infectious diseases physician and microbiologist at the Australian National University, agrees measures to tighten Sydney’s lockdown have not been successful in reducing daily numbers, and thinks action must be taken to further reduce movement and the spread of the virus.

然而, he believes measures should be based on evidence of transmission and breaches of lockdown.

“Unless we find a whole lot of people at night doing the wrong thing, a curfew doesn’t make sense.”

Collignon said the current lockdown settings would be more effective if a greater proportion of people were obeying the rules. While he said policing had a role to play in improving compliance, communicating the specifics of the rules effectively was equally important.

“I’m not sure making rules tighter for the sake of it will do as much as making sure existing rules are followed, and that only happens when the vast majority of the population understands the rules properly,“ 他说.

Collignon is sceptical of the benefit of enforcing mask-wearing outdoors across all of Sydney. 反而, he thinks mandating face shields indoors among essential workers would do more to limit spread of Covid, pointing to studies out of China that people with glasses were significantly less likely to contract Covid.

“If you’re worried about particles in your nose or mouth, you need to be worried about your eyesA face shield on top of a mask provides an extra 20% reduction in transmission risk,“ 他说.

In a stark admission last week, Berejiklian said the majority of new cases infectious in the community were “derived from critical activity” – either essential workers or people buying groceries and medicines – and said further restrictions were unlikely to reduce these types of transmissions.

While retail had more lenient restrictions in the earlier weeks of Sydney’s lockdown, rules have been tightened, and only essential and frontline businesses are now allowed to open.

Detailed lists of permitted businesses have been drawn up by health authorities in NSW, as they were also done in 维多利亚 for stage-four restrictions.

然而, some non-frontline Melbourne industries, including abattoirs, were subject to strict ratios to limit onsite presence – something not currently done in Sydney.

From Saturday, construction will also be allowed to resume in Sydney, with similar restrictions to Melbourne’s stage-four rules for the industry.

Collignon, who is also a member of the Infection Control Expert Group, which advises the Australian 健康 Protection Principal Committee on infection prevention and control issues, believes measures like face shields should be implemented for essential workers, and notes that transmission was seen between essential workers “sharing tea rooms during their breaks” during Melbourne’s lockdown last year.

“If essential workers are taking their masks off to eat, they should be wearing face shields.”

Toole believes workplace ratios to reduce how many workers are onsite that were used in Melbourne should be looked at in Sydney, but says little data about what types of workplaces are hosting transmission has been provided by NSW authorities.