Untangling what Omicron means for New Zealand’s approach to the pandemic – Stuff.co.nz

As New Zealand, once again, enjoys a relatively normal summer, much of the world the UK, the US, France and Australia has seen staggering Omicron surges.

South Africa, where the variant seemingly emerged, has also seen unprecedented new highs, but cases have since fallen.

This week in Aotearoa a single Omicron case caught the public attention as the visiting DJ Dimension tested positive after leaving isolation before receiving the results of his day-9 test.

In his DJ Dimension press conference, Covid-19 Response Minister Chris Hipkins spoke of keeping Omicron out as long as possible. The underlying message is clear: Omicron is inevitable.

As the variant spreads rapidly throughout the world, there are obvious questions: what does it mean for New Zealand? How prepared are we? How well do the vaccines hold up? Is it less severe? What numbers should you keep an eye on overseas to understand Omicron?

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Most reporting on Omicron has been focused on case numbers, which is understandable. They're eye-watering. But they dont tell the full story.

There are clearly an awful lot of cases not being picked up. In New South Wales, for example, testing infrastructure is struggling to keep up with demand. And in the UK, researchers have said three quarters of all colds will be Covid. Got a sniffle? You probably have Covid-19.

Secondly, Delta is still out there. In the week ending December 18, the US Centers for Disease Control and Prevention (CDC) said Omicron accounted for 73 per cent of cases in the US. It has since revised this down to 60 per cent, meaning many of those hospitalised in the US right now likely have the Delta variant.

Its still not clear what the future holds for Delta, by the way. It may well be displaced or vanquished. A small study out of South Africa suggests people with Omicron may have increased immunity against Delta.

Delta is falling in the UK at present but how much of that is the booster campaign and how much Omicron is difficult to judge, Professor Paul Hunter of the University of East Anglia told me.

On Thursday, there were 10,000 people in hospital with Covid-19 in England. There are a few things to keep in mind here, though.

The first is: are people in hospital with Covid or because of Covid? This is hard to untangle and something Stuff has reported on in New Zealand.

According to Chris Hopson, the head of NHS Providers, people need to be wary when interpreting UK hospital data.

Talking to trust chief executives this morning, whats very interesting is how many are talking about the number of asymptomatic patients being admitted to hospital for other reasons and then testing positive for Covid. Some are describing this as incidental Covid, he wrote on Twitter on December 28.

We should therefore be cautious about over-interpreting current raw Covid admission data. As Covid community infection rate rises rapidly due to Omicron, we will get more cases of this type of incidental Covid-19 in hospital. Raw data doesnt distinguish between the two.

Data from last week suggested about 30 per cent of Covid cases in UK hospitals were incidental. These numbers will vary by country. And remember, these cases can still put pressure on hospitals as patients need to be isolated.

Finally, there are ICU admissions and deaths. This will likely offer a clearer picture of the impact of Omicron but keep in mind people dont die of Covid (or end up in hospital) the day they get it. The lag to a death could be weeks.

In the UK, deaths and ICU admissions have held steady, but its too early to be sure if this will hold. Incomplete data over Christmas is also an issue.

Whats more, the majority of cases in the UK have been among younger people, who are much less likely to suffer severe Covid outcomes. However, it is concerning that cases in the elderly, who are at most risk, are seemingly on the rise.

Its also worth noting that while case numbers are unprecedented, there were more than 1000 people dying every day with Covid in the UK last winter. The UKs current totals are nowhere near those levels.

Hunter said itd be best to wait at least another week before reading too much into the UK data on the worst Covid outcomes.

No. Its not.

In early 2020 when Covid arrived in New Zealand, the entire population was naive (or susceptible) to the virus. This is why we called it novel.

Almost two years on, some 90 per cent of the eligible population is vaccinated. This matters above all else. Third doses are being rolled out to supplement immunity. Vaccines for children are imminent. Covid treatments are emerging. We have better testing. We know much more about the virus.

Whats more, Omicron appears to be less severe than its predecessors.

Sir John Bell, regius professor of medicine at Oxford University, said this week that Omicron is not the same disease we were seeing a year ago and high Covid death rates in the UK are now history.

For instance, people with the latest variant are 50 to 70 per cent less likely to need hospital care, according to UK Health Security Agency data, which compared it to Delta.

A new report from South Africa has found Omicron led to significantly less severe disease than Delta. But the authors warned: Care should be taken in extrapolating this to other populations.

This is good news. But untangling why Omicron appears less severe is tricky.

Is it because most people are now immune having had Covid or been vaccinated? Is it because the majority of cases are in young people?

Or is it intrinsically less severe? The UKs Imperial College has found that Omicron was somewhere between 0 and 30 per cent intrinsically less severe than Delta. This essentially means people who are unvaccinated or have never had an infection may face less chance of going to hospital with Omicron than its predecessor.

It may be, however, that the reason Omicron is less severe is that there are simply far more breakthrough infections. That is, the variant is excellent at infecting people who have been vaccinated and therefore have good protection against serious illness.

Fiona Goodall/Getty Images

People are tested at a pop-up Covid-19 testing station in Woodall Park car park in Narrowneck, Devonport.

Simply put, it may be infecting a lot of those people who may never have caught Delta, as that variant doesnt bypass the vaccines as effectively. And those vaccinated people are almost all going to end up being OK.

Or is it a mix of all of these?

Hunter explained that the mutations within Omicron primarily allow it to bypass the protection offered by antibodies essentially our first line of defence.

But the good news is the immune system has a range of different soldiers T cells, for one, which are much longer lasting.

There are very few mutations on those parts of the virus primarily targeted by cytotoxic T cells, and T cells are probably more important for protection against severe disease, Hunter says.

A pre-print study posted this week backed up this point, finding the protection offered by T cells, brought about by vaccination or infection, holds up very well to Omicron.

Unfortunately not. We still have the small percentage of a big number is still a big number issue.

A Scottish study that found a two-thirds reduction in hospitalisation notes: The combination of increased risk of transmission and immune evasion of Omicron mean that any advantage in reduced hospitalisation could potentially be exceeded by increased rates of infection in the community.

In a piece for The Age, epidemiologist Tony Blakely offered a good explanation of what this balancing act looks like.

With Delta, we expect something like 350 to 500 people in hospital on any given day following an announcement of 1000 new cases about two weeks prior. With Omicron, we are heading to something like 100 people in hospital on any given day for 1000 daily cases two weeks earlier.

He suggests 20,000 cases a day could translate to 2000 hospitalisations, and that may simply be too high for healthcare systems even though the newer variant produces less severe outcomes in infected individuals.

Peter Dejong/AP

People walk down a normally bustling shopping street in Amsterdam on Monday, December 20.

The NSW picture is vital to New Zealand. Their vaccination rates are comparable and neither New Zealand nor the Australian state have endured Covid case numbers comparable to Europe.

This is, paradoxically, now a weakness for New Zealand. Our success at keeping Covid-19 out may mean were more at risk.

At least in the UK and South Africa Omicron is rather less likely to put you into hospital than Delta, and probably even less likely to put you into an ICU bed though how much that will transfer to New Zealand is unclear with the much lower past infection rates you have had, Hunter says.

Covid hospitalisations are on the rise in NSW, as are ICU totals. Its also worth keeping in mind, as Blakely tells me, there will certainly be people in hospital in NSW with Delta. (Remember the lag).

Omicron moves incredibly quickly. According to a CDC analysis, it may only take three days for people to become contagious. With Delta, it was somewhere between four and six.

This, combined with the fact the variant is better than Delta at bypassing the protection the vaccines offer against infection, means its incredibly difficult to stop.

Kevin Stent/Stuff

Vaccinator Taylah Lardelli draws a dose of the Covid-19 vaccine at Pacific Health Plus, Porirua.

According to a UK analysis, two doses of the Pfizer vaccine are 60 per cent effective at stopping symptomatic Omicron in the first two to four weeks after vaccination. But that protection falls off to only 35 per cent after 10 weeks. A third dose bumps that back up to about 70 per cent, but that protection also seemingly wanes.

The report suggests two doses should offer good protection against severe disease. There are significant caveats around everything with Omicron, however. Were still learning about this variant.

In a Twitter thread, biology and biostatistics professor Professor Tom Wenseleers suggested the sheer speed at which Omicron moves may mean its peak is shorter, but much sharper.

This would still mean a huge number of cases but not necessarily over a long period of time. Again, well see.

The traffic light system was designed to support mass vaccination to control Delta case numbers. So far. its worked well. Because of the exceptional vaccination rates, case numbers have been kept in check. But things may change as our immunity wanes.

The Omicron reality is quite simple: New Zealands red light setting along with high vaccination rates (and an excellent booster roll-out) won't necessarily stop Omicron. Vaccines for children, along with a good booster roll-out supplemented by public health measures, will only slow it down.

New Zealand started by eliminating the virus, now its suppressing Delta, but it may be yet another new strategy is unavoidable, Professor Michael Baker told me.

He describes this as mitigation. It would simply mean doing what we can to keep hospitals from being overwhelmed.

Theres a cruel reality here. Eliminating Omicron is unrealistic. Even effective suppression or keeping numbers low will be incredibly taxing.

Baker is not being defeatist. Ideally, hed like to stop people being exposed to any coronavirus. But that may not be possible in 2022. And it may be that the costs of chasing tight suppression are too high (and not politically viable) particularly if Omicrons mildness holds up.

Well have a more complete picture in mid-January, Baker says.

Professor Michael Plank agreed. Depending on how the hospitalisation numbers and severity estimates pan out, he says, it may be that countries employ a range of measures like masking, capacity limits and working from home mandates to limit, but not stop, spread.

Essentially this means accepting Omicron but just spreading the huge case load over a longer time period, so hospitals can cope. You may recall the phrase: flatten the curve.

Baker said it would be optimum to keep Omicron out until were better prepared until the immunity gaps are plugged, until more vulnerable people have had their third vaccine dose. The Government clearly agrees.

In his piece in The Age, Blakely outlined what loose mitigation may look like in NSW or Victoria: about 10,000 cases every day. Thats probably manageable, he suggests.

Blakely points out there are a number of considerations at play whether a new better vaccine is imminent, and what Long Covid looks like after Omicron but it may be that a manageable number of cases of this variant is better in the long term.

Frank Augstein/AP

Shoppers crowd together at Covent Garden in London on Wednesday, Dec. 22, 2021.

First, if everyone is going to be exposed to Covid-19 at some point (which seems likely), then it would make sense for those who refuse to get vaccinated to take their chances with Omicron; the next variant may be more virulent again, he writes.

It may be that tight lockdowns put pressure on Omicron, but the question is: where does that leave us in the medium to long-term?

And as liberal writer Owen Jones points out in The Guardian, support for lockdown-like measures has disintegrated in the UK.

Overwhelming support for lockdown persisted for so long because there seemed to be a stable exit route: that mass vaccination of the population would protect the NHS from the menace of Covid-related collapse.

Now that certainty has evaporated an endgame no longer seems sure and the prospect of open-ended restrictions looms.

Consider what that means here: New Zealands first lockdown eliminated the virus. The 2021 lockdown failed to eliminate Delta but allowed mass vaccination. The end goal of another large-scale lockdown to slow down Omicron would be murky at best, and hugely politically challenging given the high vaccination rates. The Government has signalled it will only use lockdowns if absolutely necessary.

That said, University of Sydney epidemiologist Professor Alexandra Martiniuk suggested that tighter restrictions may be unavoidable. Too many cases could push countries into a corner where theyve no choice but to react.

You may have heard NSW Health Minister Brad Hazzard warning the public that everybody should expect to get infected by the Omicron variant.

RHETT WYMAN/Sydney Morning Herald

New South Wales Health Minister Brad Hazzard.

Thats pretty gloomy, but is he wrong?

I asked Hunter, Plank and Martiniuk about this.

Basically he is correct, Hunter replied. Nothing in medicine is 100 per cent, but the large majority of people will get Omicron.

Martiniuk said she did not know. But wouldnt you rather delay getting it until a few years from now? Wouldnt you rather get it when there are better treatments and better vaccines?

Plank certainly doesnt agree with Hazzards messaging. He sees it as defeatist, but he acknowledges the minister probably has a point. The sheer speed at which the virus spreads, and the fact it evades vaccination, means that once it starts spreading its going to infect a lot of people although maybe not everyone.

But that doesn't mean you dont do anything to try and slow it down or stop it, Plank says, And there are still vulnerable groups, and we really need to keep those groups in mind.

Continued here:

Untangling what Omicron means for New Zealand's approach to the pandemic - Stuff.co.nz