NZ has just passed a million Covid cases but University of Auckland Senior Lecturer Dr David Welch says the real number of infections could be more than double. Video / NZ Herald
ANALYSIS:
Those hoping for more freedoms with a move from orange to green are likely to be disappointed by today's review of the traffic light setting.
The Omicron outbreak has unfolded largely as expected, with a peak firstly in Auckland and then the rest of the country, followed by aflattening of case numbers which have then crept up in the last month.
Reported daily case numbers peaked at about 20,000 in early March, with hospitalisations peaking at about 1000 in late March, and deaths at 18 per day in early April. These fell post-peak to about 7500 cases, 350 hospitalisations, and 10 deaths per day.
But health officials are anticipating a winter peak of up to nearly 2600 hospital beds taken up by Covid, RSV, flu and other respiratory illnesses.
That's about a third of the total number of resourced hospital ward beds in the whole country, which leaves not nearly enough of a safety margin to ease the few restrictions that remain.
Projection of hospital beds cumulatively occupied with Covid, RSV and respiratory illnesses including flu this winter. Source / Ministry of Health
The winter peak is based on modelling that director-general of health Ashley Bloomfield revealed recently.
He presented two scenarios. The lower-transmission one peaked at 500 Covid cases in hospital in September. The higher-transmission one peaked at just shy of 1300 hospitalisations in mid-August.
Hospitals were planning for the high-transmission scenario, he said.
Add RSV and other respiratory illnesses, including the flu, and hospitalisations are modelled to peak this winter at about 2500 beds for a period of six weeks.
Flu has already started to spread in Dunedin and Queenstown.
Factor in, too, the context of a hospital system that's usually under pressure in winter, even in pre-Covid times, and how stretched the health system was in March when the hospitalisation peak was lower than the modelled winter peak.
This would all make it very surprising if the Government signalled a move to green at any stage until winter was well and truly in the rearview mirror.
The modelling numbers are based on a presumption of staying at orange. At green, there are no restrictions.
"I think green seems inconceivable at the moment," University of Otago epidemiologist Professor Michael Baker says.
Modelled hospital bed occupancy for Covid cases this winter under a high transmission scenario (B) and a lower transmission scenario (A). Source / Ministry of Health
That currently centres around Omicron subvariants BA.4, BA.5, and BA2.12.1, which are becoming more prevalent overseas as they appear to be more infectious than the BA.2 variant, which dominated New Zealand's first Omicron wave.
Each of those subvariants has been detected at the border in New Zealand, though none are yet to get a grip on community transmission.
BA.4 and BA.5 are behind a recent surge in case numbers in South Africa, and they might also be starting to trigger a new wave in the UK.
There is nothing to suggest at this stage that any of them cause more serious illness than BA.2.
But there is emerging evidence on how little immunity you might have against them if you've already had BA.1 or BA.2.
"The data I've seen shows that, if you haven't been vaccinated, then prior infection with BA.1 or BA.2 doesn't give you great immunity against BA.4 or BA.5," says Covid-19 modeller Professor Michael Plank.
"But if you've been infected and vaccinated, you've got much more robust immunity against getting severely ill. So the important message is that we shouldn't rely on prior infection to provide our immunity.
"It's really important to go and get a third dose, if people haven't already had it. Otherwise, you're risking getting severely ill, because it's likely that people will be reinfected for a second time at some point."
There are several ways that pressure on hospitals can be eased this winter, including the flu vaccine rollout, and a fourth Covid vaccine dose for the elderly, vulnerable and immunocompromised, which is expected to start in June to maximise winter immunity.
By then, up to half the country might have been infected, but how much population immunity this provides will depend on which subvariants are spreading in the community.
Officials are also somewhat flying blind when it comes to the level of population immunity because the Ministry of Health's prevalence survey - which would potentially tell us a lot more - is still only scheduled to be actioned "over the coming months".
Political decisions on traffic light settings are always a balancing act, and today's context is a Labour Party that's been sliding in the polls and a population that is well and truly over Covid.
The Australian election result this weekend also shows how quickly keeping Covid in check for much of 2020 and 2021 can become irrelevant in the eyes of voters.
The New Zealand Government's elimination strategy, with an implicit goal to prevent as many Covid deaths as possible, resonated with voters as well as public health experts.
But that's all changed with Omicron. Now the stated aim of government restrictions is not only to keep the health system from being overwhelmed but to cause the least amount of disruption in people's lives.
The price of that, since Omicron arrived, has been 1000 deaths linked to Omicron - with Covid causing 46 per cent and contributing to 23 per cent of them; 17 per cent were unrelated to Covid, and the rest are still being investigated. Almost 90 per cent of those who died were aged 60 and over.
The pivot to fewer government mandates and more personal responsibility has made life harder for the vulnerable and immunocompromised. Why would the parent of an immunocompromised student send them to a classroom where students don't have to wear masks?
The implicit question underlying the level of restrictions is: how many deaths are too many?
A party calling for fewer restrictions is essentially saying that the price of keeping the current level of safety is too much. One calling for more controls is saying that too many preventable deaths are happening, and we should all carry the burden of more restrictions.
Based on current settings, it seems the Government's answer to how many Covid deaths are tolerable is about 2500 to 3000 a year.
