The data that shows why it's IMPOSSIBLE to achieve Covid Zero despite some suburbs within Sydney and hotspots having NO cases and 90% fully vaccinated - and there are important lessons for Melbourne

Some suburbs within Sydney Covid hotspots are recording zero active cases - with some postcodes also having 90 per cent of residents fully vaccinated.

Anomalies within pandemic danger zones offer a lesson to Melbourne as active Delta numbers surge into triple digits in the city's troubled western suburbs.

But Covid Zero is impossible to achieve in densely-populated areas with more essential workers and in many cases, lower levels of English proficiency.

In a particularly dark day for New South Wales, 1,431 new cases were recorded on Friday, with 12 deaths.

The Liverpool local government area is one of 12 LGAs subject to a 9pm-to-5am curfew and residents can't venture more than 5km from home unless they provide an essential service.

In Liverpool and Casula, there are 734 active cases, as of Friday night.

Suburbs within Sydney Covid hotspots are recording zero active cases despite residents earning less money - and in some postcodes 90 per cent of residents are fully vaccinated. Within the Liverpool council area, Badgerys Creek has zero active cases

But within the same council area, Badgerys Creek has zero active cases even though household incomes in this suburb are lower than Liverpool.  

In this suburb, earmarked as an airport site, 93.7 per cent speak English only at home and 82 per cent were born in Australia. 

By comparison, in Liverpool less than half or 45.2 per cent of people were born in Australia and only 33.4 per cent spoke English at home.

Liverpool Labor councillor Nathan Hagarty, who represents the North Ward, said his 'cash poor' constituents in Badgerys Creek were more likely to live on a large block and be able to avoid crowded workplaces.

'Pretty much, the houses out there are acreages so people are spaced out a bit,' he told Daily Mail Australia.

'You're not living in an apartment and people are employed there usually on the land or through the trades so they're not essential workers and they're not working in confined spaces.

In Liverpool and Casula, there are 679 active cases (pictured is a woman on Macquarie Street in Liverpool) 

'They're probably asset-rich but cash poor and a lot of them run their own businesses or are sole traders.'

Mr Hagarty said people in Liverpool and Casula were more likely to work in service jobs and found the state government messages on Covid to be confusing because many residents didn't have a great grasp of English.

'The messaging from the government, they used the same kind of messaging that worked on the Northern Beaches and the eastern suburbs - which was people with higher English-language proficiency, perhaps high levels of education, and mainstream media consumers,' he said.

'Out in this part of the world, people speak many different languages, they get their news from a bunch of different sources and there are a lot of informal media networks through WhatsApp and channels like that.' 

Liverpool Labor councillor Nathan Hagarty, who represents the North Ward, said his 'cash poor' constituents in Badgerys Creek were more likely to live on a large block and be able to avoid crowded workplaces. By comparison, people in Liverpool were more likely to work in a service job and have less English language proficiency

Within the Liverpool council area, Edmondson Park has Australia's highest immunisation rate with 90 per cent of residents aged 16 and over fully vaccinated - an achievement not even seen on Sydney's wealthy North Shore.

Indian is also the most common ancestry in the suburb, where the active case count of 57 is less than 10 per cent of nearby Liverpool.

Mr Hagarty said Edmondson Park residents were more likely to have heard about the more contagious Delta strain from their relatives or news outlets in India, which encouraged them to get jabbed.

'The government needs to take a really good look at why somewhere like Edmondson Park has the rates it did and why others don't and learn lessons,' he said.

'There's a very high South Asian population, a lot of them are professionals so I think there's a combination of being able to navigate the system and know how to get vaccinated but also they'd be getting information from their homeland in India and seeing the impact of the Delta strain there.' 

Like Sydney's west and south-west, Melbourne's western suburbs has higher case numbers in areas where residents are more likely to be migrants or people on lower incomes. Victoria now has 1,180 active cases with 103 of them at Tarneit (pictured during the lockdown)

James Cook University epidemiologist Professor Emma McBryde said zero Covid was not achievable now.

'Lockdown was a great weapon last year. It allowed Australia to achieve elimination for many, many months. But with the new Delta strain, the game has changed completely,' she told the ABC's 7.30 program.

Professor McBryde said prolonged lockdowns would do more harm socially.

'Things like mental health, children missing school, people losing their jobs and livelihoods,' she said.

'They are a very blunt instrument and we have to reconsider all of the rules, now that we're no longer trying for elimination.'

In the Penrith council area, Orchard Hills has zero active cases even though neighbouring Colyton has 549 active cases.

But in both suburbs, two-thirds of residents were born in Australia and speak English only at home.

 James Cook University epidemiologist Professor Emma McBryde said zero Covid was not achievable now

In Colyton, a significantly higher proportion of people work as taxi drivers, making them more likely to come home and unknowingly pass on the virus to family members. 

Like Sydney's west and south-west, Melbourne's western suburbs have higher case numbers in areas where residents are more likely to be migrants or people on lower incomes.

Victoria now has 1,180 active cases with 103 of them at Tarneit in Melbourne's far west. Nearby Altona has 100 active cases.

The combined active case count in these suburbs almost adds up to Victoria's new daily case tally of 208 announced on Friday.

But unlike Sydney, most Melbourne suburbs still have active case numbers in the single digits.

No local government area of Melbourne yet has a majority of the working age and adult population fully vaccinated.