The spread of the virus through households creates costs higher than for isolation in hotels when families are large and living at close quarters as in Melbourne's public housing towers.
As governments start to return to a new normal, people with disabilities in care facilities are still in serious danger of being left behind during the coronavirus pandemic.
The internal density and layout of buildings are key factors in COVID-19 transmission risk. This is not an argument against high-density cities, some of which have successfully contained the virus.
As New Zealand prepares to ease its lockdown from April 28, new COVID-19 clusters are likely to emerge – but a combination of testing and contact tracing should be able to stamp out major outbreaks.