Elimination of the virus ("Zero covid")

Many independent public health experts advocate that we should move to eliminate the virus from the UK. For example, in July 2020, the Independent SAGE group published their report A better way to go: towards a zero covid UK [1]. It was accompanied by a letter to the Chief Medical Officer [2].

This means reducing the incidence to close to zero, or in practical terms less than 1 case per million population per day.

The theory is not difficult. There are no or very very few infectious long term carriers of the virus, and so the virus has to keep finding new hosts to infect as infected people recover from their infection (or die). If the virus does not find a new host, the chain of infection dies out. So it is just necessary to implement enough measures to keep the R value below 1 wherever community transmission is occurring.

This has been the successful strategy of China, Taiwan, South Korea, Vietnam, New Zealand, and many other countries more here, and it is extraordinary that it is not already the strategy of the government in the UK and elsewhere. The key action shared by the successful countries seems to be setting up a very efficient find, test, tract, isolate and support system.

The chart above shows countries that have reduced the covid-19 incidence to below or close to 1 case per million population per day (with the residual cases being almost entirely in incoming travellers). Because it is hard to see very low rates on a linear chart, the next chart is added to show the same data using a logarithmic scale for the y-axis.

For comparison, the next chart is the same as the first chart, but with the addition of the UK. Rates are shown as per million population to facilitate comparison. By taking the right decisions, the UK could have a much lower rate. Several parts of the British Isles have been free of covid-19 for long periods. Unsurprisingly, these are in the more remote areas: Isle of Man, Orkney, Shetland and the Western Isles of Scotland. Currently (5 November) Orkney and Western Isles have been free of new cases for over 7 days.

The better virus control does not come at an economic cost because those countries with the best virus control tend to have the least economic damage [3].


Further information


Objections and explanations


In order to be absolutely sure of zero new infections in a country, you'd need to test everyone in the population in a very short timeframe to check nobody has the virus. If you don't do that, given the number of asymptomatic cases, it could pop up anywhere in any number of small outbreaks.
That hasn't been necessary in the countries that have eliminated the virus. Asymptomatic people don't seem to remain infectious long term.

Nobody has any idea how far it has already spread in any population, given that many infected people have no idea whether or not they've had it.
We have a good idea of where the virus is provided there is a proper system of find-test-trace-isolate because most cases are symptomatic.

Keeping restrictions for a long time will result in more rule breaking
Yes, that's another reason why we should eliminate the virus, so we can more or less get back to normal.

A substantial portion of the population don't want to be traced
It's not necessary to trace everyone who might have the virus. To eliminate the virus, we just need to keep the R value below 1, and the chains of infection will progressively be broken. The lower the R value, the quicker this will happen.

There would be restriction of personal international and internal travel
Most people cannot afford much more international travel if they are to stay within their individual lifetime carbon budget of 40 tonnes per person (https://www.carbonindependent.org/93.html). Travel is easier where the virus has been eliminated.

How can we feasibly eliminate a virus that has been spreading in the community for months?
We estimate how contagious it is by the R value - how many cases each case spreads to.
Without any measures it was about 3 - under max measures, it's about 0.3.
We just need to keep R below 1 and the virus dies out.
The length of time it has been spreading is not relevant.



References
[1]A Better Way To Go: towards a Zero COVID UK (July 2020) https://www.independentsage.org/wp-content/uploads/2020/07/20200717-A-Better-Way-To-Go.pdf
[2]https://www.independentsage.org/wp-content/uploads/2020/07/20200713-Letter-to-Chris-Witty-SDK.pdf
[3]Greg Jericho The Guardian (12 Sep 2020) Regardless of Covid restrictions, if people are dying in large numbers your economy is stuffed https://www.theguardian.com/business/commentisfree/2020/sep/13/regardless-of-covid-restrictions-if-people-are-dying-in-large-numbers-your-economy-is-stuffed

First published: 20 Jul 2020
Last updated: 6 Nov 2020