Predictions of 50,000 daily Omicron infections by Waitangi weekend have not borne out and New Zealand Covid-19 modeller Michael Plank believes he knows why.
A report from rnz in late January explained New Zealand could be facing 50,000 daily Omicron infections by Waitangi weekend, according to modelling by an overseas health research organisation, saying the virus would be “peaking at about 80,000 cases each day just a few weeks later”.
“The Institute for Health Metrics and Evaluation (IHME) projections, predicted an outbreak in New Zealand lasting about three months, with death rates projected to total more than 400 by May 1. Daily fatalities are predicted to spike at about 10 through mid-March.
“There are also warnings this country's ICU capacity will come under "extreme stress" through February and March,” the report said.
However on Friday February 4, nine people are in hospital with the virus, including only one person in an intensive care or high dependency unit as 209 new cases were recorded in the community.
Modelling from an international agency predicted there would be around 50,000 cases a day in NZ by Waitangi weekend. (Source: 1News)
RNZ reported IHMEs modelling with the "most likely" scenarios are based on vaccinations carrying on at the expected pace, mask use staying about the same, and 80 per cent of those already vaccinated getting a booster within six months - the numbers do drop if 100 per cent get their booster and then again with 80 per cent of people using masks whenever they're out in public.
“Under the 'most likely' scenario, daily infections start to rapidly take off almost immediately: By February 1 at just over 13,000, by the 9th hitting about 62,000, and peaking in mid-February at over 81,000,” the report states.
Te Punaha Matatini's Michael Plank is a well-known modeller in New Zealand. He told 1News the modelling, was not done in New Zealand and “does not take into account our local situation very well”.
“Those numbers also refer to infections, which is not the same thing as cases. Cases rely on people getting a test - and with Omicron when people are vaccinated, a lot of those infections will be mild.
“Not all of them but lot of them will be – and may even be asymptomatic and so not all of those people will get tested and show up in our case numbers,” he said.
“And even the ones that do, it will take a week to two weeks after they get infected for them to get tested and for that to come through in the numbers.
“So however many infections we have on Waitangi Day, that won’t actually show up in our numbers for a couple of weeks yet,” Plank said.
He said there are likely to be “significantly more” infections in the community than whatever the number of cases is reported on any given day.
“That’s just a feature of a growing outbreak when you have cases growing and you’re not going to find every last case,” he said.
Plank said at the moment, case numbers are doubling about every four to five days.
“If that trend continues, I think we are likely to hit around 400 cases a day, probably around the middle of next week”.
He said that was a better trajectory than had been seen overseas, a sign the traffic light system was working.
“It’s all about slowing things down and spreading out the load on our healthcare system because that’s what we are trying to achieve here.”
He said it was likely there may be a peak of Omicron numbers adding to pressure on the hospital system. But, he said, that would be mitigated by people getting their booster shot.
Plank didn’t want to diminish the importance of overseas data but said the unique situation in New Zealand, along with our population numbers made local modelling more accurate.
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