Covid-19: What does the red light setting actually do to combat the Omicron outbreak? – Stuff.co.nz

Aotearoas new red light setting is up against the most transmissible variant of Covid-19 to date. Is it up to it? National Correspondent Katie Kenny reports.

The new Covid-19 protection framework, known as the traffic light system, was designed to slow the spread of the Delta variant of Covid-19. Now, in the face of a new and more infectious variant, were sticking with it to see us into this phase of living with the virus.

As of January 23, following the detection of Omicron in the community, New Zealand is at the most restrictive red setting.

This isnt a lockdown. With vaccine passes, most parts of life can continue as usual. Domestic borders are open, workplaces and schools are open, you can visit cafs and bars, and go to the hairdresser and gym.

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The main restrictions involve wearing masks on transport and at most public, indoor venues, and limiting gatherings to 100 people if everyone has a My Vaccine Pass.

These are the rules that will apply even when there are as many as tens of thousands of cases a day.

For a country that got through the initial period of the pandemic with the lowest Covid-19 mortality in the OECD, high levels of personal freedoms, and relatively good economic performance, the dramatic shift in strategy can be disconcerting.

Our approach is comparable to how many European countries have dealt with Omicron. So, will it make any difference?

Covid-19 modeller Professor Michael Plank says while well still see cases go up rapidly, the public health measures in place during the red setting will help slow the spread of Omicron.

We know mask use makes a significant difference, as does limiting larger gatherings.

Hes reluctant to commit to numbers, but says these measures could reduce transmission by 20 per cent or even 30 per cent, compared to unmitigated spread.

Even relatively small changes in behaviour can make a big difference over time, because they reduce the rate of exponential growth.

We know a flattened curve means New Zealands healthcare system has a better chance of coping with demand. It also reduces the number of infected people who have to take time off work to isolate.

In places like South Australia and Queensland, we saw daily case numbers grow from single digits to over a thousand in about two weeks. But in Aotearoa, nearly a fortnight on from those initial community cases, weve managed to delay the start of the exponential growth phase.

On the eve of Waitangi weekend, cases were climbing, but not with the speed weve seen overseas.

On January 23, the seven-day rolling average of community cases was 25. On February 4, it was 128.

James D. Morgan/Getty Images

A Covid-19 drive through testing clinic in Byron Bay, Australia. (File photo)

We have several advantages over even Australia. The main one, as Prime Minister Jacinda Ardern has repeatedly highlighted, is our ability to roll out booster shots ahead of widespread community transmission. (New South Wales, for example, was already grappling with Delta when Omicron arrived in December.)

Two doses of the Pfizer Covid-19 vaccine offers less protection against symptomatic Omicron than with Delta, according to data from the United Kingdom Health Security Agency. But double-vaccinated people are still well protected against hospitalisation and death.

A booster dose offers greater protection against transmitting Omicron to others and further reduces the chance of more serious infections.

As of Friday, February 4, more than 94 per cent of the eligible population over 12 were double vaccinated, and 36 per cent over 18 were boosted (boosters arent yet available for those younger than 18).

On top of restrictions and vaccinations, peoples behaviour will dictate the rate of Omicron spread, Plank says. But thats also the hardest thing to predict.

Restrictions are one thing, but its possible people will decide to avoid riskier activities or delay them or find alternatives.

New Zealand was notoriously compliant with lockdowns in 2020 and 2021. According to Google mobility reports, the countrys first level 4 lockdown saw a staggering drop in Kiwis accessing parks, shops, restaurants and workplaces even places deemed essential during the period. It was a similar story nationwide in August 2021.

Kathryn George/Stuff

New Zealanders have generally followed lockdown rules closely during the pandemic. Now, many continue to stay home, even when thats not required.

But would we still reduce our movements, even if we didnt have to?

Approaching Christmas, people in Britain lost their appetite for eating out as Omicron spread. The number of seated diners was at its lowest level since restaurants reopened indoors in May, after a winter lockdown.

Its possible we'll see similar or even more caution exercised in New Zealand as cases rise.

Meanwhile, the Netherlands is currently easing some of the toughest Covid-19 restrictions in Europe. This is despite rising case numbers but in response to waning public support for the measures.

In a blog post for Otago Universitys Department of Public Health, Professor Nick Wilson and others wrote: New Zealanders may also take an Omicron outbreak more seriously than the populations of other countries and hence be more vigilant than expected with mask use (including using higher quality masks, such as N95s), physical distancing and such measures as working from home.

As an early indication, Google reports to January 28 against a baseline of early 2020 show New Zealanders are going out for shorter amounts of time and visits to retail, recreation and workplaces are slightly down.

Unlike Australia, Aotearoa has had the opportunity to apply increased public health measures to lower the Re value of the outbreak, Melbourne-based New Zealand epidemiologist Professor Tony Blakely says.

Remember the R number? Its the average number of people that one infected person will pass the virus on to. The R0 is essentially the R number when theres nothing to stop the virus. And then theres the Re, the transmission rate once the virus is spreading in the community, but there are obstacles in place to slow it down.

Using a simple mathematical model for illustrative purposes, Blakely outlined two potential scenarios in a population the size of Victoria.

The first, depicting the virus being allowed to spread through the vaccinated population without additional public health measures, the second, with measures similar to New Zealands red setting being introduced at 50,000 daily new infections.

Keep in mind, infections include undiagnosed and asymptomatic cases.

The former scenario sees an Re value of 2.5. With additional public health measures (such as boosters, mask-wearing and limiting large gatherings), the Re is reduced to 1.5. The first wave is sharp, and steep. The second peaks lower and cases are spread over a longer time period.

To be clear, this is just to give us a sense of how turning up restrictions can flatten the curve, which in turn reduces the maximum load on health services. What happens in New Zealand may well be very different.

The sort of restrictions New Zealand already has in place, potentially capping the Re at 1.5 from the get-go, could nearly halve the peak of our wave, Blakely says. But the number of people infected by the waves end is not that much different.

While the idea of 50 per cent or more of the country getting Covid sounds scary, he says theres no need to panic. As long as you protect your vulnerable they can hunker down and get boosted you can allow it to wash through the young, fit and healthy in a managed way.

He adds public health measures mean were unlikely to see the number of Covid-19 cases in hospitals peak at 4000, as early estimates suggested.

More recent modelling for an Omicron variant outbreak of Covid-19 in New Zealand by the Institute of Health Metrics and Evaluation suggests hospital admissions could peak at 2790. But Blakely is more optimistic.

The peak in New South Wales saw 2800 people in hospital on any given day. Victoria peaked at 1200, he says. I suspect youll peak at 1000. Or, if you flatten the curve well, perhaps 500-700.

Its too difficult to say at what point cases will level off. As the expected, significant minority of people who worked from home and avoided crowds through the peak reappear, its possible theyll be oxygen to smouldering embers of the outbreak. This will prolong the wave, but at a more manageable level.

No one can really, totally remove themselves from society, Plank says. I think were likely to see a peak and then a rapid decline.

Some have asked: Would lockdowns make a difference?

Weve previously used lockdowns successfully to eliminate the virus, Plank says. We also used them in response to the Delta outbreak to give us time to get vaccination numbers up.

Were not in that situation any more. Yes, were in the middle of a booster roll out but within a month, the vast majority of adults will be eligible for theirs. So were within striking range of high booster coverage, too.

ANDY MACDONALD / STUFF

A Covid-19 pop-up testing station at the Tahuna Beach Holiday Park.

In coming weeks and months, we can also expect to see more border cases coming into the community.

The issue with a lockdown is: what would be the exit plan?

So, what does all of this mean in the long term?

The Atlantics James Hamblin in February 2020 posited that roughly 40 to 70 per cent of the world would get infected with the virus that causes Covid-19. In December 2021, as a tidal wave of Omicron swept across the US, Hamblin referred to his initial prediction as an understatement.

The prediction was based on a basic model of herd immunity thresholds for a respiratory virus but not one that managed to evolve and re-infect people as quickly as SARS-CoV-2 has, he wrote.

Hes quick to point out infection isnt the same as sickness, and not all sickness is the same. This disease can feel like nothing, or it can send you to the ICU for weeks, only to leave with permanent organ damage.

WARWICK SMITH/Stuff

A vaccination centre in Palmerston North.

Populations with high levels of vaccination will be less affected by Omicron. But in the US, for example, thousands of preventable deaths are occurring largely as the result of people declining vaccination.

Out of self-interest, I ask Plank: If I dont catch Covid-19 in the next three-to-six months, does that mean I could avoid it, forever?

I dont think Covid will go away, he says. I think well be dealing with it in the community for the foreseeable. The level of threat it poses has already diminished thanks to the vaccine. And it will continue to diminish as people have immunity from both vaccines and prior infections.

But that doesnt mean it wont be a public health issue, and that we can forget about it. This wont be the last variant well see.

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Covid-19: What does the red light setting actually do to combat the Omicron outbreak? - Stuff.co.nz