Public health experts advocate a two-pronged approach to tackling COVID-19 – vaccination programs and exposure reduction (including mask wearing, physical distancing and area-level lockdowns).
These strategies are not mutually exclusive, with international evidence showing that vaccination strategies need to consider both social conditions and population mobility – factors like finances, housing security, as well as the need or not to travel for work.
In both the United Kingdom and the United States, pandemic strategies blind to social conditions have led to certain groups and communities being harder hit in terms of both infection rates and deaths.
In countries like England, for example, mortality rates are more than twice as high for people living in the most deprived areas, compared to those living in the most affluent.
What's the right COVID-19 risk to live with?
Our newly developed Neighbourhood Employment and Housing Precarity (NEHP) Index is designed to help policy makers quickly identify areas that are particularly vulnerable to both the virus and social distancing measures like lockdowns.
This information can be used to better target vaccination programs and support.
It confirms that in both Sydney and Melbourne, those areas with high concentrations of people who work in occupations that require close contact with others or who cannot work from home, and that experience household crowding and/or housing insecurity, are also the areas with higher rates of COVID-19 infections (see maps below).
Why employment and housing?
Both housing and employment conditions shape people’s daily lives and routines.
When employment circumstances that increase mobility converge with certain household characteristics –like overcrowding – they together have the potential to greatly affect COVID-19 transmission rates.
Identifying vulnerabilities in advance puts us ahead of the virus in planning our public health responses and in coordinating these responses across cities and relevant government departments.
For example, we’d argue that vaccination strategies need to be place-based, prioritising areas where employment characteristics and housing conditions make populations especially vulnerable.
This would make vaccine delivery more efficient, and also allow governments to forward plan support for locked down suburbs.
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How does the Index work?
The NEHP Index jointly analyses employment and housing factors that increase the need for people to move around and reduce their ability to distance from others.
We mapped the Index to Melbourne and Sydney to investigate its correlation to COVID-19 cases and assessed the benefits of using spatially informed metrics like this in COVID-19 policymaking.
The NEHP Index combines secondary, publicly available Census data, as well as data modelled from the Census and international open-source data to efficiently map the vulnerabilities of different areas in an accessible way.
It’s constructed from information that classifies workers by whether they can work from home and how close they are to others in the workplace, as well as data describing area-level household crowding, housing affordability stress, homelessness and access to emergency funds.
These datasets were standardised, weighted equally and summed up to create a single, composite score for every neighbourhood across the two cities.
The Sydney neighbourhoods rated highest for vulnerability in our Index are predominantly located in the south-west and western regions of the city and are among the areas most impacted by the city’s latest outbreak.
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We found the same correlation last year during Melbourne’s second and deadliest wave of COVID-19. Again, Melbourne areas that ranked highly on the NEHP Index also experienced the greatest COVID-19 burden (see Map 2 below).
What does this mean for tackling COVID-19?
In hindsight, the Index tells us that Melbourne’s suburb-based lockdowns may have been undermined by insufficient consideration of who would be more likely to travel for work or live in insecure and crowded housing in these neighbourhoods.
But despite this warning, New South Wales’ initial containment strategy replicated this mistake, again failing to consider that those living in these lockdown areas are also largely those who sustain Sydney’s essential services and so need to continue to work and travel.
It’s welcome news that the NSW government has since announced a vaccination program targeted at essential workers in Sydney’s south-west and western suburbs who are unable to work from home.
However, if social conditions and mobility had been at the fore of decision-making, this policy could have been identified and enacted earlier to better contain the virus before infections soared.
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We are continuing to learn the hard way that locking down communities isn’t effective if it isn’t coupled with adequate testing capacity, targeted and easy-to-access vaccination, as well as the necessary support for affected populations.
Spatial indices like the NEHP offer policymakers options for more efficient and effective allocation of resources, as well as data-driven insights for future planning and support.
Even Australian cities that have yet to face a major outbreak ought to consider targeting their vaccination rollouts in neighbourhoods that are more mobile and whose residents are likely to be in close contact with others.
This could protect these cities against the virus taking hold undetected and reduce the spread of transmission.
Regardless of the source of initial infection, the risk of further transmission is linked to the working, living and mobility characteristics of different populations.
If we are to disentangle these effects we will need socio-spatial tools like the NEHP Index.
Where to from here?
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While there have been national strategies that focus on vaccinating occupations that might expose vulnerable populations to the virus (like those people working in aged care), our Index highlights that vaccination strategies need to be cognisant of both social vulnerability and mobility.
This information can inform vaccination rollouts in cities by identifying where mobile workers live.
Importantly, it can help us provide targeted and appropriate support for people in locked-down areas where residents have less control over contact with others in the workplace and in their homes.
The NEHP Index can be replicated for most major Australian cities, and its occupational data can be mapped to other international contexts.
In conjunction with greater consideration of mobility trends, this could be an important part of our pandemic planning toolkit going forwards – at home and abroad.
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