Coronavirus: Modeller believes around half of New Zealand's population has been infected with COVID-19

Based on what has been seen overseas and on the modelling, around half of the population will have been infected with COVID-19, says Te Pūnaha Matatini contagion modeller Dion O'Neale.

Last week Director-General of Health Dr Ashley Bloomfield said thousands of new cases of COVID-19 were being reported every day in New Zealand, but it was likely to be half of the number of actual cases.

As of Sunday, there had been 1,039,575 cases of COVID-19 reported in New Zealand.

But Te Pūnaha Matatini contagion modeller Dion O'Neale told Morning Report the government's estimate was possibly on the low side.

"We'd think that probably by this point around half of the population, very roughly, have been infected with COVID-19," O'Neale said, but it didn't mean the other half of the population would get COVID-19.

"Part of that is going to be the people who haven't got COVID so far, they're going to be the people who have been taking more precautions than other people and so almost by definition, if they are able to take better precautions, and they can keep those up, they can continue to be the people who don't get COVID if they're up to date with all of their vaccinations and boosters and things like that."

It was a marathon, not a sprint, he said.

"On the other hand, people who have had COVID, we know that reinfection is an issue, we know that new variants evade immunity from ... infection of previous variants.

"It almost becomes a game of many people are going to get COVID, you'd like to get it as few times as possible. It's not just a case of once and done, it's once and then potentially a few months later, again."

People who didn't take precautions after infection were likely to get COVID again, O'Neale said.

He said it may not be a case of needing tougher restrictions but needing better messages about the restrictions we do have.

"Maybe that might mean a little bit of support and help for people to follow some of those restrictions.

"Take mask wearing as an example of something that's relatively low cost, it's low impact, it's something that as individuals we're all able to do. There are a lot of people out there who are wearing masks, a lot of them aren't wearing them that well - they're wearing them over their mouth, they're not wearing them over their nose for example."

Messaging to explain that COVID is an airborne disease and that a masks needed to be worn in a way that filters the air, was needed to help people to stay safe, he said.

"We've been dealing with a pandemic for a long time, it is going to be fatiguing. On the other hand, something that is fatiguing is recovering from COVID and people having long COVID and post viral syndromes are a classic disease that leaves people fatigued."

"If you think the fatigue's bad from wearing a mask, imagine what it is from that post viral syndrome."