Analysis: Pundits want to see New Zealand ditch its elimination goal in favour of a Sweden-style herd immunity strategy. What would that look like? Marc Daalder reports
The return of Covid-19 to New Zealand last week and the resultant Level 3 lockdown in Auckland has led to a renewed push by pundits for the Government to abandon its elimination strategy in favour of a Sweden-style herd immunity approach.
“This hopeless strategy of perfection, of elimination, entails destroying our economy and quality of life in an endless pursuit of the unobtainable,” Damien Grant wrote in Stuff.
“The strategies Ardern and Collins are publicly committed to are therefore not sustainable beyond this latest incident. Managing the entry of Covid-19 into the population sometime over the next 18 months is now the only realistic option,” Matthew Hooton opined in the New Zealand Herald.
For Newsroom, talkback radio host Ryan Bridge wrote, “It’s becoming abundantly clear the Prime Minister’s sworn mission of stamping Covid-19 out of New Zealand is neither sustainable nor the right thing, morally, to do”.
On Monday, anti-lockdown epidemiologist Simon Thornley’s Plan B group ran a day-long symposium with lockdown sceptics from across the globe.
But does their case stack up?
The straw man
Michael Baker, a member of the Government’s technical advisory group for Covid-19 and a professor at Otago University’s Department of Public Health, said the premise of these arguments is a straw man – they are arguing not against New Zealand’s actual Covid-19 strategy but a simplified caricature of it.
All three columnists presume that the elimination strategy entails a move to Level 3 or 4 whenever cases of Covid-19 are found in the community. But that’s not true, Baker says.
“In March, we had very few alternatives if we were going to keep the virus out. Whereas now, we should be able to do a more nuanced approach, which we are doing. At one level, the classic example is having regional differences in alert level and also not going straight to Level 4,” he said.
“Both of those signal a major advance in capability and thinking.”
Baker said the response to this new outbreak – which has seen nearly 100,000 Covid-19 (or one sixth of all tests conducted so far) tests carried out in five days and more than 80 percent of close contacts traced within 48 hours – proves New Zealand should be able to contain small outbreaks at Level 2.
“The other three things we’ve got now are high-volume testing, a well-developed contact tracing system and the use of masks to suppress transmission. All of those things, when they work really well, decrease the need for a lockdown.”
This counters Bridge’s argument, based on an anecdotal conversation with Health Minister Chris Hipkins, that the country’s contact tracing system is not “gold standard”. The performance of the system over the past week has exceeded the key performance indicators set by Dr Ayesha Verrall’s April audit of contact tracing.
Still, the question must be asked: Why couldn’t Auckland stay at Level 2 for this outbreak?
Siouxsie Wiles, a microbiologist and expert on infectious diseases at the University of Auckland, suggested that we slipped up by not doing more community testing.
“At Level 1, everybody’s going, ‘Well, it’s not here, so we shouldn’t need to get tested. I just have a cold.’ But this is what it’s going to require,” she said.
The testing reluctance also found a home on right-wing talk radio, with Mike Hosking telling listeners on August 3 – four days after the onset of symptoms for one of the cold store cluster cases – that getting tested “doesn’t make sense” and was just a political ploy by the Government to better its chances at the election.
On July 19, just eight tests were conducted in New Zealand outside of the managed isolation and quarantine system. Just 12 days later, a worker at the cold storage company Americold developed Covid-19 symptoms. They would later test positive for the virus.
When Cabinet was told last week there were four new cases of Covid-19 with no obvious links to the border or overseas travel, officials did not know how widespread the virus was. The subsequent taking of 95,000 tests across the country has turned up just 54 other cases, indicating that the outbreak is relatively limited.
If more robust community testing had been carried out, then the chain of transmission might have been caught closer to its point of origin, allowing officials to deal with it in a Level 2 environment.
And that capacity is there, Baker says, pointing to the past week of testing and contact tracing.
The counterfactual
Wiles says anti-elimination advocates haven’t done the work to vet the counterfactual – what would life look like in New Zealand if we went the herd immunity way instead?
“What does living under Plan B look like? It looks like people dying and people being unwell.”
Naturally, the lockdown sceptics reject that argument, pointing to Sweden as an example of a country that simultaneously ameliorated the health and economic impacts of Covid-19. But did it, really?
Half of the anti-lockdown argument is premised on the notion that the virus has not been that bad in Sweden. Hooton pointed to a breakdown of cases and deaths by age group, writing, “In fact, right up until age 50 or even 60, Sweden suggests Covid-19 represents no material risk to anyone, being an issue mainly for geriatric medicine”.
He suggests the Covid-19 death-to-population ratio in Sweden – it has killed 0.06 percent of Swedes – is no big deal and “as intensivists and geriatric medical experts share data to improve treatment, the death rate will surely fall even lower than in Sweden”.
But 0.06 percent of New Zealand’s five million is 3,000 people – about 10 percent of all the people who die in a given year in New Zealand.
And that’s just the pandemic so far. Contrary to Bridge’s implication and Grant’s outright assertion that the outbreak in Sweden is slowing, the country’s rolling seven-day average of daily new cases have actually jumped by about 40 percent over the past fortnight.
That figure now stands at about 281 new cases a day over the past week for Sweden. The peak seven-day average of new cases for New Zealand’s entire experience with Covid-19 came near the start of lockdown, when we reported an average of 72.1 new cases a day.
The last time Sweden had that few cases was March 12. Sweden hasn’t gone a week without at least one death from Covid-19 since March 16.
Of course, focusing only on deaths ignores the documented longer term impacts a bout of Covid-19 can leave even younger patients struggling with.
These include brain damage, insomnia, vertigo, irregular heartbeats, long-term shortness of breath, hypertension and joint pain. New Zealander Hayley Wolters recently wrote about her experience with what is colloquially called “Long Covid” – symptoms staying long after the virus has left the body.
“It’s been 21 weeks since I got sick. I haven’t drawn a full, clear breath since day one,” she wrote.
“The list of symptoms I continue to have all align, including tachycardia, heavy lungs, aching back and chest. Heart pains. Fatigue when I try to exercise – a few weeks ago a 10 minute walk would wipe me out. Sugar, alcohol and too much caffeine cause flare-ups. I went dancing for an hour and relapsed for a week.”
To be sure, there are negative health impacts from lockdowns as well. Despite effectively erasing the winter death spike, as the below chart from Stats NZ shows, the Level 4 lockdown in March and April led to deferred health procedures that could have longer-term consequences.
“Some 30,000 elective surgeries were delayed because of the first lockdown and some have still not caught up,” Bridge wrote.
But pretending that the same hasn’t occurred in Sweden is disingenuous. There, the health system had to defer even immediate operations in order to make space for the wave of Covid-19 patients requiring hospital-level care – in one week, from April 1 to 7, there were 301 new cases requiring intensive care.
The wait time for elective surgeries in Sweden has grown by three months. The number of organ transplants carried out in Sweden has fallen dramatically. As of early July, lung transplants had fallen by 58 percent, heart transplants by 38 percent, kidney transplants by 30 percent and liver transplants by 10 percent.
The economic pitch
Bridge’s lambasting of the impact of lockdown on New Zealand’s elective surgery waitlist while ignoring the impact of the pandemic on Sweden’s is typical of the anti-lockdown arguments, Wiles says.
The same principles are applied to the economy, where the columnists argue Sweden has seen the benefits of avoiding lockdown.
“The idea that Sweden doesn’t have any restrictions is a bit farcical, actually,” Wiles said. The data bears this out.
The Oxford Policy Stringency Index was developed to rate how strict controls on social and economic life are in different countries battling Covid-19. While New Zealand’s Level 4 lockdown was rated 96.3 out of 100 and its Level 3 was 83.33, Levels 2 and 1 are much more relaxed than what other countries are experiencing.
From May 14, when New Zealand moved down to Level 2, we have enjoyed more freedoms than the Swedes. Even now, two-thirds of our population operates in a less strict environment than Sweden. In fact, since February 28, when New Zealand reported its first case of Covid-19, we have spent more time with laxer measures than Sweden than the inverse.
Studies of consumer spending data shows purchases fell by 25 percent in Sweden and 29 percent in Denmark, which instituted a strict lockdown.
Other economic indicators for Sweden are not looking wonderful either.
The IMF predicts Sweden’s GDP will fall by 6.8 percent this year and then increase by 5.2 percent the next. By comparison, New Zealand’s GDP is expected to fall 7.2 percent this year and then rise by 5.9 percent the next – although this projection was made prior to the move to Level 2 nationally and Level 3 in Auckland last week.
Unemployment in Sweden rose from 6.7 percent to 9 percent for the year ended June. In New Zealand, year-on-year unemployment was flat at 4 percent. An April projection from the IMF estimates Sweden will end the year with 10.1 percent unemployment, while prior to the latest lockdown, New Zealand was expected to reach around 10 percent unemployment at the end of the September quarter.
Westpac economists have come to similar conclusions as the Government, predicting that the new lockdown is a smart economic move.
“If the Alert Levels are not raised further, and things return to normal within a couple of weeks, the economic impact will be relatively small,” chief economist Dominick Stephens wrote in an August 14 bulletin.
“We have calculated that, for each week that Auckland is at Level 3 and the rest of New Zealand at Level 2, about $300m of economic activity is foregone. This equates to 0.5 percent of quarterly GDP. But, during a brief lockdown, a higher proportion of that lost activity would be recouped shortly afterwards, so the actual lasting economic damage would be significantly smaller than this $300m figure.”
If alert levels were to increase nationwide and the lockdown to be extended until it lasts a total of six weeks, the post-lockdown economic spike would mean that the entire experience would just shave off 0.5 percent of GDP in the net, the economists found.
The real danger was in a scenario where the virus was able to run rampant, Stephens wrote.
“If New Zealand loses control of the virus, that would be a game changer for the economy. Around the world, we are seeing a sharp divergence in the economic performance of countries that have control of the virus, compared to countries that do not. Countries that have implemented successful lockdowns are generally doing much better economically than countries that have not – illustrating that the ‘choice’ between health and economy was always a false dichotomy.
“All of this suggests that if New Zealand goes into another successful lockdown, it will suffer only incremental additional economic damage, whereas if the virus gets out of control the economy would take a much bigger hit.”
Herd immunity
Of course, this latter bit of Westpac’s analysis is premised on a scenario where the virus is able to tear through vulnerable communities – the elderly, those with preexisting conditions and marginalised groups – while the death toll racks up.
Lockdown sceptics insist there is a better way to go about introducing Covid-19 to New Zealand, with one goal in mind: herd immunity.
Hooton wrote about “managing the entry” of Covid-19 through keeping vulnerable populations locked away while young and healthy people continue to live life at Level 1, catching the virus and building up immunity across the population. He wrote about concerns that a vaccine, if it ever arrives, will be ineffective, leaving New Zealand shut away from the world while an otherwise-immune global population gets on with everyday life.
Putting aside the fact that few countries beyond Sweden have intentionally taken the herd immunity approach – China, which is expecting a GDP rise of 11.5 percent this quarter, is shielding more than a billion people from the virus – Hooton’s argument is difficult to see working out in reality, Wiles says.
The vulnerable populations Hooton wants to shield make up large swathes of New Zealand’s society. There are 1.089 million people aged 60 and over in New Zealand.
If they were to experience the same death rates as Sweden in their respective age brackets, 161 people between 60 and 69 would be killed by Covid-19, 508 people between 70 and 79 would be killed, 791 people between 80 and 89 would be killed and 353 people who were aged 90 or over would be killed.
Staving off those 1,813 deaths would require shutting those 1 million New Zealanders away from contact with the rest of the population while the virus worked its way through younger people and the country eventually built up herd immunity, according to Hooton’s formula.
The same would have to be done for those with conditions that render them more vulnerable to severe illness or death from Covid-19. The United States Centers for Disease Control says this includes type 2 diabetes (which a quarter of a million New Zealanders suffer from), moderate-to-severe asthma (which 700,000 New Zealanders take medication for), cancer (which 27,000 people are diagnosed with a year), chronic obstructive pulmonary disease (which 1.5 percent of Māori over 45 have) and obesity (which affects 30 percent of adults including 66 percent of Pacific adults and 48 percent of Māori adults).
The CDC also says current and former smokers are at added risk of severe illness from Covid-19 – 1.5 million New Zealanders fall into this category. Of course, some of these numbers overlap, but they still indicate that large segments of New Zealand society would have to live under Level 3 or 4 conditions until herd immunity was achieved.
Then there are the young people, who have a greater chance of surviving – Hooton correctly notes that no one in Sweden below the age of 19, which accounts for one fifth of the population but just one twentieth of cases, has died of Covid-19. As noted above, they are still at risk of serious complications – and economy could struggle to operate with many young people sick and all vulnerable populations working from home or not working at all.
… simple back-of-the-napkin math indicates some 15,000 to 30,000 New Zealanders might have to die to achieve herd immunity.
“Forget about death, what about illness? Can our economy cope with the number of people who would be sick for, potentially, months at a time?” Wiles asked.
This massive undertaking would be engaged in in the hopes of reaching herd immunity. But is that something that can even be achieved?
“Sweden, with its 10 million people, went for herd immunity and appears over the worst of its Covid crisis with fewer than 6000 deaths; almost all of these as a result of a failure to insulate rest homes,” Grant wrote.
Has Sweden really achieved herd immunity? We’ve seen above that the case count there is beginning to accelerate once again – something that seems unlikely to happen in a country that has reached herd immunity. The country’s top epidemiologists promised that some 40 percent of the population would be immune by May, but antibody tests carried out at the end of that month showed just 5 percent seroprevalence nationally and 10 percent in hard-hit Stockholm.
If Sweden still has yet to come close to the required herd immunity threshold – something scientists estimate will be between 60 and 70 percent – then the road ahead is still daunting. Without a vaccine, reaching 60 percent herd immunity would require infecting 60 percent of the population.
On current estimates of an infection-fatality rate of 0.5 to 1 percent – something Bridge indicated was perfectly tolerable despite being five to 10 times more severe than typical pandemic influenza – simple back-of-the-napkin math indicates some 15,000 to 30,000 New Zealanders might have to die to achieve herd immunity.
There is also conflicting evidence over whether long-lasting antibodies develop in response to mild infections, indicating that severe infections may be required to develop immunity.
There is also uncertainty around how effective antibodies might be at granting immunity – those 5 percent of Swedes might not be immune just because they have antibodies.
Experts are increasingly doubtful that herd immunity can be achieved without a vaccine.
In the absence of compelling evidence to the contrary, should New Zealand be a guinea pig?
“I still don’t understand what their alternative looks like, other than privileged people living their lives while less privileged people get sick and potentially die,” Wiles said.
“Yes, we are learning to live with [Covid-19]. And the alternative strategy, the Plan B, is learning to die with it.”
