Almost 28,000 New Zealanders could die of Covid-19 in a "worst case scenario" if the current eradication plan fails, new modelling shows. But one author of the reports says a "best case scenario" could see less than 100 deaths.
Director-General of Health Dr Ashley Bloomfield said the modelling showed that "without the actions currently being taken, the uncontrolled spread of Covid-19 would exact a high price in New Zealand in terms of its impact on our health services, including our intensive care units, and deaths".
"All of the scenarios show an unacceptable level of deaths in New Zealand without strong action. We can see these scenarios playing out overseas already."
"Even with the sorts of strong measures we have in place to stamp out the virus, the modelling is still predicting there could be a heavy toll on our health system and loss of life."
In a potential worse case scenario, in the case that attempts to eradicate the virus fail in New Zealand, the health impact on Kiwis could see 3.3 million contracting the virus with symptoms, 146,000 of those would need to go to hospital, 36,600 would need critical care in an ICU and 27,600 could die.
Eighty-nine per cent of those deaths would be people aged 60 and over, and deaths would likely be higher for Māori and Pacific people and those living in deprived areas.
"This death toll would far exceed the death toll for NZ from World War One (18,000 deaths) and from the 1918 influenza pandemic (9000 deaths)," the report reads.
Another report looks at scenarios that consider the health outcomes if New Zealand's current eradication strategy fails, taking two levels of contact reduction between people (a 25 per cent drop for six months, and 50 per cent for nine months).
For the scenarios, 44 to 64 per cent of population get sick, 22,200 to 32,000 need to be hospitalised, 5,540 to 8000 need critical care and 2,770 to 4000 would need ventilators and deaths would be between 8560 to 14,400.
"If New Zealand fails with its current eradication strategy toward Covid-19, then health outcomes for New Zealand could be very severe. If interventions were intense enough however, in some scenarios the epidemic peak could still be suppressed or pushed out to the following year (at which time a vaccine may be available)," it says.
However, one of the reports' authors, Professor Nick Wilson, told 1 NEWS the chance of the worse case scenario eventuating was under five per cent.
"These are all bad outcomes if New Zealand's elimination strategy doesn't work, we're all hoping it's got a reasonable chance at success."
In the "best case scenario", New Zealand would be looking at possibly under 100 deaths.
He said that could still see cases in the community, and "some of those cases will end up in hospital and ICU and unfortunately die, but that’s way better than what we’re seeing in other countries if our elimination strategy works".
Professor Wilson said he hoped a "huge effort" would be put in over the next few weeks to identify any cases in the community and to break lines of transmission.
A report for the spread and health impact of Covid-19 in New Zealand saw an estimate of 65 per cent of the population (3.2 million) contracting the virus but only 34 per cent would be symptomatic - if the disease was "substantially uncontrolled".
"However, these could well be over-estimates if the disease is less transmissible in New Zealand than China," the report reads.
Modelling estimates in that scenario 336,000 people likely to require hospitalisation.
Between 12,600 and 33,600 deaths were estimated in a "substantially uncontrolled" environment. It says that mortality estimates could be over-estimates if treatment options improved, the spread is slower, if control measures work and if a vaccine was developed later this year.
"As in previous epidemics and pandemics of infectious respiratory agents, severe disease burden is likely to fall unequally on Māori, Pacific peoples, and the elderly," it reads.
The modelling also showed potential future scenarios, saying that if "Covid-19 follows the same patterns as previous pandemics, there may be a relatively high and heavily unequal hospitalisation and mortality burden on Māori and Pacific populations".
"Elderly are particularly at risk, and Māori and Pacific elderly even more so, and from younger ages."
"It’s critical to understand that each of the models presents a number of potential future scenarios, none of which are future predictions," Dr Bloomfield said.
"The key value of modelling like this is to assist with planning and decision making at an early stage, when prevention measures can have greater effect, and along with a range of other information, modelling can guide decision makers."