The only way to contain coronavirus cases in NZ is to go to Alert Level 4 for a brief period.
New Zealand currently has an unknown number of coronavirus cases wandering around our community. A number of observations support this, first is the experience of many other countries, second is the sudden growth in confirmed cases, third is that we have a cohort of international arrivals (and returning New Zealanders) who came to NZ between March 5-15th. This means they arrived before the mandatory 14-day quarantine, but still within the virus incubation period. Virtually all our new cases are from this cohort.
We now have a 4-level alert system. This is an excellent tool to get everyone on the same page and clearly to communicate both risk and required actions.
We should be at Level 4 right now.
This would allow us to reduce to Level 3 and then Level 2 as quickly as possible and avoid protracted disruption. I will explain.
The target we are chasing is invisible and our confirmed data is always behind the brute facts of the situation. In a situation like this the ONLY strategy that can succeed is to draw the circle of containment as wide as possible and then move inwards. This means setting Alert Level 4 right now, stay at home.
Over the next 12 or so days, ALL the coronavirus cases would then reveal themselves with symptoms developing (or if it is a mild case the infection passing almost unnoticed) without infecting anyone else. Once we have identified ALL the cases, then they go into isolation and we have stopped the spread.
After two weeks, towns, cities or regions with no cases revealed can be set back to Level 3 and even Level 2 and business can carry on. Towns or regions with cases might hold Level 4 for another week. But everyone can very quickly get back to Level 2.
We can then release the strict controls and just deal with one case at a time as they crop up, all of which (theoretically by that point) will be cases of returning New Zealanders who will reveal their symptoms while in 14-day self-quarantine and this will not be problematic.
We then implement widespread temperature checks, hand washing, stigmatization of coughing etc. But business can carry on.
What this implies
Whether Winston Peters’ encouraging of New Zealanders overseas to return is helping or facilitating the problem. Places like Wuhan now look relatively safe. As long as people don’t transit through airports where they could catch the virus, there are many places that might be safer than attempting to return, and the likelihood of bringing disease back into a quarantine zone.
In the future when we get warning of a novel outbreak we ought to immediately and dramatically close down the world for 2-3 weeks for exactly the reasons that I’ve outlined above. This should have happened around Jan 20th. Previous times that we might have taken this approach would have been with SARS, Ebola, MERS, and now Coronavirus. This is about 4 times per 20 years, or about 20 times per century. It is far preferable to suffer 2 weeks of GDP losses twenty times than 18 months once. This is a no brainer, but the mechanisms need to be coordinated ahead of time. A 20:1 false positive rate needs to be seen as acceptable.
Hopefully, New Zealand decision makers see the logic in this and raise us to Level 4 today, for a period of 2 weeks to minimise our losses.