Covid 19 coronavirus: Where are NZ's most vulnerable places?

New Zealand's vulnerability to Covid-19 has been laid out in maps showing major cities - but also remote communities - among the most threatened spots.

In a just-published study, Dr Jesse Wiki and Canterbury University colleagues pulled together a mix of risk factors to get an unprecedented picture of our susceptibility.

The analysis, drawing on the 2018 Census and existing databases, generally found that older populations and those with compromised health had higher vulnerability.

But other socioeconomic and demographic factors also mattered.

"Interestingly, many areas of high vulnerability were located in small towns and communities, particularly those with large Māori populations," Wiki said.

"This is an important consideration given that such areas typically have less access to healthcare and fewer resources."

The study focused on three main factors - health, sociocultural and socioeconomic - and explored how levels of vulnerability changed with each.

These maps show the vulnerability of people to Covid-19 in different parts of New Zealand, as determined by health, sociocultural, and socioeconomic factors. Credit: Wiki et al

When health factors and populations older than 65 was used as the combined measure, vulnerability was generally higher in cities than rural areas - potentially due to higher demand for healthcare.

When "sociocultural" factors were the key measure, major cities in the North Island and areas like the East Cape emerged as the most vulnerable - something largely down to higher proportions of ethnic minorities.

"Being a bicultural country with an indigenous Māori population and mix of ethnicities living in both population centres and outside of them, adds to the complexities of defining what vulnerable populations are and where they reside," the researchers wrote in the paper.

"This is important, as such differences have previously been shown to have implications for health inequity and health outcomes in New Zealand."

Combined with older populations, the "sociocultural" measure put central and north Auckland, along with west Christchurch, among the most vulnerable places.

"This is likely influenced by the Asian ethnic group, which was shown to have a high loading on this factor and have high population numbers in these areas."

Under the "socioeconomic" factor, meanwhile, rural areas of the North Island stood out alongside South Auckland and the east of Christchurch.

That could be explained by higher deprivation and smoking rates, larger Māori populations, and lower awareness of services.

"By providing a spatial understanding of vulnerability this research can guide health‐focused policy to areas where interventions may be needed and generates information that can mitigate potential inequality in government response," Wiki said.

"It also provides support for the idea of targeted protective measures and precautions that can be effective locally, important considerations in the overall policy response."

Otago University epidemiologist Dr Amanda Kvalsvig said risk factors around Covid-19 were complex, and could play out as a "syndemic" situation where people suffered multiple disadvantages and health issues all at once.

"It's complex: for example, one of the effects of colonisation is that Māori and Pacific populations overall have shorter life expectancy than other ethnicities.

"So there are a lot of people who are simply missing from the map, and others who are vulnerable at a relatively young age."

While no analysis could capture all of that complexity, she said the new study's approach was a "huge advance" on looking at health factors one by one - and could help our response to the next pandemic.

These maps show New Zealand's three main cities' vulnerability to Covid-19, across three main risk factors. Credit / Wiki et al

Associate Professor Collin Tukuitonga, associate dean Pacific at the University of Auckland's Faculty of Medical and Health Sciences, said the new paper confirmed findings from earlier Covid-19 studies.

He noted how the study pin-pointed older age as the most significant risk factor; ethnic minorities and those living in socioeconomically deprived areas were also affected.

"Areas with high Māori and Pacific populations are among the most vulnerable, including South Auckland and Porirua.

"Identifying where these areas of high vulnerability are located allows for better targeting of resources."

The study follows debate around which groups should receive the Covid-19 vaccine first, with the Government prioritising South Aucklanders over 65 among the rollout's second tier.

Yesterday, Associate Health Minister Ayesha Verrall said one of the risks was if a part of the country or a particular ethnic community wasn't vaccinated to a high level.

"Perhaps we could get outbreaks in that group. What we're working on now is how to understand that so that we can have a sophisticated understanding of what the public health consequences will be of reopening borders."

She said the Government would have more to say on that later this week.

A related issue was whether vaccinated people could still carry and transmit the virus, she said.

"There has been a suggestion that being vaccinated still allows you to be a carrier. I think the evidence is tipping against that, but we need a definitive position on the science."

Covid-19 Response Minister Chris Hipkins added that questions remained about people under 16.

"We don't have a vaccine approved for the under 16, and that's obviously a significant portion of our population.

"But we will know more in the second half of the year around whether Pfizer will be available for that group, or whether one of the other vaccines we have access to might be suitable for that group.

"I saw the comment [Tuesday], 'it's not rocket science'. Well, it's also not that simple either, and being simplistic about it could potentially be a very bad thing if you don't get the right people being vaccinated at the right time with the right vaccine."