Has New Zealand Made the Public Health Investments to Come Out of Coronavirus Lockdown?

Dr John Snow is considered one of the founders of modern epidemiology, in part because of his work in tracing the source of a cholera outbreak in Soho, London, in 1854, which he curtailed by removing the handle of a water pump. Snow’s findings inspired fundamental changes in the water and waste systems of London, which led to similar changes in other cities, and a significant improvement in general public health around the world.

Some political journalists in New Zealand, like Henry Cooke have amped up the pressure of the country coming out of lockdown (going down the alert levels) by indicating it is a political decision, subject to coalition politics and something to do with the public wanting takeaway food and preventing movement over a long holiday weekend.

I would contend it is none of these things. The decision should be based on science.

In New Zealand alert level four (full lockdown) has gone well. The transmission rate of Covid-19 has reduced below 1. Recoveries outnumber new infections. New Zealand is very fortunate as the hard work the country has done has been effective. The virus is dying off. This gives us more options than many other countries we like to compare ourselves with.

The task as New Zealand goes down the alert levels (progressively comes out of lockdown) is to keep the transmission rate below 1. This will prevent an exponential outbreak from reoccurring which would require a return to alert level four.

What is required to keep the transmission rate below 1?

  1. Secure borders. Quarantining of all new arrivals into New Zealand. This is the biggest causative risk for a new Covid-19 outbreak occurring. Secure borders will minimise new infections coming into New Zealand. A system of compulsory quarantining new arrivals in hotels is in place and appears to be well functioning.
  2. Testing, testing, testing. Anyone who has a Covid-19 type symptom should be tested as soon as possible. This will catch any new Covid-19 outbreak as early as possible. Currently testing numbers are high, and this task appears doable.
  3. Contact tracing. If an outbreak is detected, the contacts of the infected person need to be quarantined faster than the virus can spread. This process does not need to be perfect, but it does need to keep the transmission rate on average below 1, so that viral spread dies off. If each infected person passes the virus to more than 1 person, then the outbreak’s growth goes exponential which can quickly overwhelm public health control measures. Currently this task appears to be the most challenging.

Moving down the alert levels is an enormous economic advantage. This means investing in the above tasks is hugely valuable. It has been suggested that for every $million invested in a Covid-19 public health initiative has a return in the $billions.

If that means investing in a workforce of thousands of contact tracers at a cost of some $millions, then New Zealand should do that. If that means issuing every New Zealander with a health tracking card at a cost of $100 million then New Zealand should do it.

It also means if some extra time is required to put in place the public health initiatives to safely go down each alert level then we should take that time. The hard work the country has done in controlling the virus should not be jeopardised.

The main question our top elected politicians should be asking officials when deciding whether to go down an alert level is whether there are adequate interventions in place to keep the transmission rate below 1.

Further, I think it would be helpful if the PM or senior government officials like Dr Bloomfield explained this decision-making process to the public.

This thinking mostly comes from John McDermott who you can listen to here when he was interviewed by RNZ (note the audiotape interviews him in two parts with another economist Brad Olsen in the middle).

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