Sunday, 30 August 2020

Not enough worst-case thinking

A University College of London Vice-Provost and clinical academic lays out scenarios

I worry we're not worried enough about Scenario 4.

There are four likely scenarios for exiting this pandemic:
  1. Development of a vaccine. A vaccine that successfully blocks transmission would be the most ideal strategy. Over 170 companies are now developing vaccines with three in large scale, clinical trials. It is essential that vaccines show not only an immune response (which they all do) but that this is sufficient to protect against severe disease and against transmission of the virus. There are, however, concerns that any protection may not break the transmission cycle and that immunity will be transient, as is the case for natural immunity of people, infected with coronavirus. A new vaccine typically takes four years to develop. It is my view that a vaccine is unlikely to be successfully developed that leads us to exit the current crisis. The other concern is the recent report of the infection of an individual, who had already had coronavirus. Re-infection was with a mutated strain and this suggests that vaccines will need to deal with natural variation or target the invariable part of the virus.

  2. The SARS-CoV2 naturally loses infectivity, as may well have occurred during the Spanish influenza outbreak in 1918-20. However, coronaviruses do not mutate at the same rate as the influenza virus.

  3. We develop herd immunity: an R0 of 2.6 means that approx. 62% of the population would need to be immune, at any one time, in order to develop herd immunity. Herd immunity values are currently approximately 0.5-15% in different areas of the country. Any recurrent waves of infection will be required to acquire a 62% target and that would assume that immunity is long lasting, rather than transient.

  4. The virus becomes endemic: this would mean the virus circulating in the community with intermittent flare ups that are handled by local lockdowns and standard NHS treatment. Interpretation of the current data is that case numbers are going up but there are no significant numbers of admissions to hospitals, at least in London. This likely reflects the testing of younger, more mobile people who do not succumb to the symptoms of coronavirus whereas, in the past, the people, who were tested, were those who had been admitted to hospital.

Thinking hard about the worst case makes all options look worse. 

But before that - some cause for optimism. A vaccine may be more likely than scenario 1 suggests. Saloni Dattani reviews the evidence and the forecasts here.  

But let's go with a worst-case where either a vaccine isn't successful, or where vaccines need boosters so frequently and where new strains requiring new vaccines keep emerging, so even 100% vaccination implies new outbreaks in the absence of tight border controls against the entry of new strains. 

The rest of the world is not following an elimination strategy. The longer this goes, the less likely it seems that they will even try. Too many places haven't the political cohesion to pull it off, even if they wanted to. 

Whatever you think about Sweden, they aren't going to hit herd immunity in Scenario 4. Herd immunity doesn't exist. It's just recurring Covid seasons, just like the common cold, except it kills a lot of people and leaves a lot of people with long term disability. 

If you want to run this direction, expect to spend a pile of money increasing capacity in hospitals and ICUs. Disability benefits will go up as reduced lung capacity prevents employment; spending on retraining would have to go up to enable shifts into other sectors. There would, in NZ, be pressure to shift ACC to cover this kind of harm, and making ACC cover health more generally rather than just accidents would probably break it. 

Expect contraction in hospitality and similar sectors as those who are risk averse take their own measures to reduce risk - at least until self-testing becomes ubiquitous. Look at the app integration of the latest Abbott test, which will show your latest test result. That test doesn't get us all the way there yet because it isn't an at-home test. We will get to at-home tests that are reliable enough while people are infectious, and cheap enough that they can be used daily or close to it. Restaurants and bars that want customers will require a recent test result as condition of entry. Risker workplaces, where distancing is harder, will test staff frequently to avoid on-site outbreaks that stymie production. When tests cost about as much as a cup of fancy coffee, workplaces will just do it. We will all be poorer by the real resources consumed in that regular testing, as compared to the pre-Covid counterfactual, but it's better than not-testing. 

There will still be recurring waves of illness, with consequent loss of life and morbidity, because even with lots of cheap tests around, some folks you just can't reach short of compulsory measures. Unless the schools are willing to enforce a regular testing regimen and to exclude students while infectious, it would at minimum come through that route. Even if each test isn't that expensive, testing each kid regularly would add an awful lot to school operating costs. School budgets would have to go up to accommodate it. 

Expect also that aged care facilities will be under heavy restrictions for the foreseeable future, with strict testing requirements for entry. 

None of that sounds good.

But neither do any of the other options. The other options may be less bad. But all options are bad. Everything sucks in Scenario 4. What sucks least isn't obvious. 

New Zealand and a small set of East Asian countries could hold to a strict elimination strategy, defend the borders, have robust systems for monitoring and trusting each other, and free mobility within the Green Zone. Advances in testing and compromises on some civil liberties for those entering the Green Zone, including rigorous testing and check-in requirements. Periods in managed isolation (NZ) or monitored and enforced self-isolation (Taiwan) can be shortened if it's possible to track people as they leave isolation and require them to self-test regularly. That increases throughput at the border without increasing risk. 

But the border will remain a horrible and costly bottleneck. I don't just mean monetary costs, obviously. There are huge humanitarian problems in imposing massive costs on travel. Remember isochronic maps? The maps that showed all the places you could get to, from London, in the same amount of time? 

We wouldn't be going all the way back to 1914, when most of New Zealand was 30-40 days from London. But coming into NZ from anywhere outside of a green zone would be a day's travel plus, at best, a week in self-isolation. 

Here's 1914 as reminder:


And here's 2016.


If the Green Zone holds, and the rest of the world remains a red zone but without formal restrictions against travel, the 2021 maps would look rather different. Basically, the map as it is in 2016, but with a big wall around an East Asian Green Zone where crossing the boundary costs somewhere between a week and a fortnight. The effective distance between New Zealand and the rest of the world would increase substantially, and we will increasingly be left behind in areas that require frequent interaction for initiating new projects and ventures. This would also severely hit the 1.2 million Kiwis born abroad and the million Kiwis abroad, any of whom may have family emergencies that require rapid travel to New Zealand from abroad. Even in the best case of this worst case, these costs will be substantial.  

Recall that the average month in 2019 saw over 250,000 Kiwis returning home from business trips, foreign study, holidays, or visits with friends and family. Current capacity in managed isolation is about 14,000 per month. Having to stay in isolation will itself deter travel. But it isn't crazy to think we'd need something like five or even ten times as much capacity in managed isolation as we currently have, once we also remember that others may wish to come here as well. If Australia gets to elimination, a lot of the burden on managed isolation goes away - Trans-Tasman is a big part of Kiwis' travel. But I do not know that they are actually trying to get to elimination, or if they will get there. 

Unless we start thinking about more practicable options. 

What can increase effective capacity while maintaining an eradication strategy?
  • A more risk-responsive set of isolation requirements, combined with options for self-isolation.
    • People coming from places outside of the Green Zone where COVID is less prevalent could have shorter isolation periods, if other risk-management protocols were put in place like post-isolation testing and location tracking. Halving the duration of isolation doubles effective capacity.
    • People willing to wear location monitoring bracelets could be allowed to isolate at home, if that home were a safe place for self-isolation - not having other flatmates, for example. I have no doubt that the American Ambassador's self-isolation in his home will be safe, and that his being there instead of in a managed isolation facility frees up a space in managed isolation for someone else. But figuring out a regime to work it all won't be easy. It requires checking that the proposed venue doesn't have others who'd be mingling. It isn't crazy to think that the costs of vetting a venue could be a reasonable fraction of the cost of providing a room in managed isolation. And while putting a monitoring bracelet on people is relatively easy in principle, keeping others from popping round for a visit is harder. The default could be managed isolation unless the traveller can demonstrate a credible self-isolation plan, but all of that will prove hard. There will be muppets who decide to have a party while they're self-isolating, and unless there are good chances of being caught and penalised for doing so, it'll be hard to deter. 
  • The whole voucher system I'd suggested to allow more facilities to come into the MIQ system - but it is still really costly both in resource and time, even if a lot of people are contributing to the costs of their own stays.
Maintaining eradication will be easier as testing improves, as regular cheap testing of anyone who is anywhere near anything that might be a risk, so it becomes far less likely that shutdowns are required to deal with outbreaks. Instead, they'd be caught more quickly, and contacts could be tested on the spot. 

A scaled up safe border is a lot more important in this world. If what we're looking at isn't a system that has to just see us through for the next year, but rather one that has to work for many years, the fixed costs of establishing better systems become worth fronting. It has to be done not just to enable Kiwis to come home, it also has to be done to mitigate some of the economic harms of Covid. There will be lots of sectors where rolling waves of disruption due to Covid are particularly costly. Some of those sectors might be able to relocate to New Zealand, if the costs of being a week or two away from the rest of the world are lower than the costs of disrupted operation. There will be piles of people who have shifted to remote work who could work remotely from here, and pay taxes here, while being paid by their overseas-based employer. 

But there are lots of options between eradication and Sweden. Canada and much of Europe are trying to keep a lid on things. Canada allows travellers to self-isolate at home, without the kinds of monitoring that Taiwan would impose. 

In the worst-case world of Option 4, everything looks worse. There will be no herd immunity. There will be no effective vaccine. There will only be dealing with it, for years and years. 

I don't think proponents of any of the possible strategies for dealing with it have carefully thought through what the "for years and years" really means. 

Proponents of Swedish approaches downplay that there will be deaths and misery for years and years, and that individual actions to reduce the risks they face also result in drops in economic activity. 

Proponents of elimination downplay the consequences of putting New Zealand back to the travel world of 1914 when the rest of the world is in 2020, and haven't thought seriously enough about what scaled up border capabilities have to look like to deal with any of this. 

And middling options that try to wipe out cases and clusters as they emerge, but without eradicating the virus, will face some of the same border costs (Canada's self-isolation requirements, for example) and ongoing restrictions and risk for those at risk, but without the potential opportunities that could come of being a covid-free place. 

I also don't think it's obvious what the best approach is.

If there were a button I could push for the set of policies that would simultaneously invest heavily in scaling up border systems (with costs recouped on a user-pays basis for overseas visitors) AND became far more welcoming to overseas arrivals by making it really easy to get a "work from New Zealand" visa for those who'd come here to work remotely for their foreign employers, making sure that there's enough managed isolation capacity to deal with it, making it easier for foreign investors to set up shop here as the Covid-free place. If it looks like normal campus life would be impossible in Covid places, a scaled-up managed isolation system could make NZ very attractive as destination. 

But I worry that the xenophobia that's come through during the pandemic makes that button impossible to push, even if the systems are safe. 

Meanwhile, the American university system is learning. They have hundreds of universities, all trying different things for dealing with the crisis. And look at what the University of Arizona has pulled off. Wastewater testing at each of the campus dorms found an outbreak before it happened, and stopped it.  
Click through and read the thread. The University of Arizona is testing wastewater coming out of each dorm facility and coupling it with rapid antigen testing. Everyone was tested before they were allowed to move into the dorms. When one dorm showed Covid in wastewater, everyone in the dorm got a quick antigen test, two asymptomatics turned up positive and were put into isolation, contact tracing is in place, and they're dealing with it.

That's what one university came up with. 

There are plenty that are providing very good examples of what not to do. But students will shift to the places that have decent systems. It'll be part of their selling point, if this is here for the long haul. 

New Zealand has one creaky system that has a hard time adapting. There have been suggestions here around wastewater testing, but has anyone started looking at testing the water coming out of each of the MIQ facilities? If it shows up in wastewater pretty early, you could run regular wastewater screening and then test everyone in the facility if the wastewater shows a positive case. 

It is hard to pick what policy options suck least when you combine worst-case thinking about the virus becoming endemic with worst-case thinking about government capabilities. Maintaining elimination has a lot of option value. Treatment keeps improving. Testing keeps improving. Systems elsewhere for getting on top of outbreaks will keep improving, and learning from experiences elsewhere will make things here better. 

But it is also easy to imagine scenarios where things abroad improve substantially for treatment, for keeping on top of outbreaks and for preventing transmission into vulnerable communities. Lots of reliance on cheap testing, layered protections for aged care facilities, isolation of cases before transmission chains can get much established. Maintaining quarantine for those arriving from abroad may not make sense in that scenario: you'd rely instead on pre-travel testing, location monitoring requirements for recent arrivals, and requirements that new arrivals do daily self-testing. We are nowhere near that making sense now. But would we be able to switch to it when and if it does make sense, under worst-case thinking about politics?

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