An epidemiologist says it's still unclear how long immunity lasts after being infected with the Omicron COVID-19 variant.
The Omicron variant - the dominant COVID-19 strain worldwide - has caused high infection rates in New Zealand since it made its way into the community.
Official figures say the number of New Zealanders who have had the Omicron variant of COVID-19 is rising towards 1 million, but modellers have said it could be as many as 2 million or more.
So after more than two years of the COVID-19 pandemic, what is the re-infection risk in people who have caught the virus?
While University of Otago epidemiologist Professor Michael Baker said that question was still unknown, he told The Project immunity with coronaviruses tended to wane quite rapidly.
"The virus has become more infectious over time - it may have reached what's called 'peak fitness' now so it may not actually get more infectious, because there isn't much room to go there."
COVID-19 may not, however, become less harsh. Prof Baker said most infectious diseases don't decline in severity over time.
"If we look at Omicron now, its severity… is very similar to the original COVID-19 virus that we saw for a whole year and it's still about 10 times more dangerous than influenza for unimmunised people.
"Unfortunately, we're now seeing this [infection] rates in New Zealand plateauing out and we're seeing this, particularly in Auckland, because that was the first place to get a peak.
"If we extrapolate it out for the rest of the year, we're maybe looking at perhaps 5000 cases a day in New Zealand, maybe 400 people in hospital, unfortunately maybe about 10 people a day dying from this infection."
Prof Baker said there was end in sight of those sorts of numbers being reported. Therefore, he said, COVID-19 reinfection would become the norm.
"I think we do need to look at what other things we can do just to dampen down transmission and reduce the harm it's causing in New Zealand."
