07 September 2020

COVID-19: WHAT DOES #NEARZERO MEAN?

In many of the posts in this blog the term #NearZero has been used to describe a type of COVID-19 strategy.  What does it mean?  How can we get there?


There are significant benefits of getting life back to as near to 'normal' as possible.  One way to do it is to get infection rates down to zero or at least #NearZero. That would be transformational:

  • The chances of meeting someone else infectious would be much more acceptable, as explained below.
  • Schools could reopen and much more easily stay open.  Even in Scotland, where infection rates are lower than England, schools are starting to have schools disruptedUniversities too, more difficult as students are susceptible to COVID-19 as young adults.
  • Everyone including those who have been shielding could go out with more confidence
  • Public transport could be used freely, albeit better with masks.  A special problem for schoolchildren and students
  • Offices, factories and other workplaces could be used with little chance of outbreaks
  • Deaths and LongCOVID would be far less than at current infection levels
  • The Night Time economy could readily implement the NTIA's recommendations 
  • Testing would be at a far more sensible scale, without the shortages that have befallen the system.  
  • The economy could thereby recover.  Indeed the current level of infections is holding us back economically.
It's worth reminding ourselves of the six risks of COVID-19, covering inconvenience, death or serious illness, and the long-term consequences of LongCOVID, even for those who were never sick enough to need hospital treatment.  Which are why a robust response to COVID-19 is needed.

Let's start with looking at other strategies that are Zero or mention Zero.


"StrictZERO" IN NEW ZEALAND

New Zealand's response to COVID-19 was "Go early, go hard".   They recently celebrated 102 days without a single person getting infected with COVID-19 on New Zealand soil.  A couple of British ladies had brought COVID-19 into the country in June, but there wasn't any onward transmission.

Restrictions had been lifted, entertainments could restart, and people could hug each other again.  Life back to normal.  Hurrah!

Then a family of four were tested positive in August.  The government put Auckland into lockdown the next day, banning residents from leaving home for non-essential reasons.  That's some 1.6 million people for an outbreak that affected less than 150 people in all.

Since then a man has died.

Even with New Zealand's geographical isolation and their strict quarantine arrangements for people arriving from abroad, the virus had still got through.

Maybe people would accept a hard lockdown again once, maybe twice.  But surely they can't keep going into full lockdown every time there's an outbreak?  There will be other outbreaks.

If this SARS2 was as deadly as two other coronaviruses SARS or MERS, which claimed one out of every three people infected, New Zealand's StrictZero approach would be essential.  Indeed needed if a future SARS3 or SARS4 was both highly infectious and highly murderous.

SARS2 is dangerous, but not that dangerous.  Whilst New Zealand's strategy has worked so far, is it sustainable?  Somehow we need to live with the virus whilst opening most if not all of society. 


ZeroCOVID PROPOSED BY THE INDEPENDENT SAGE GROUP

In early July, the Independent SAGE Group of academics and former SAGE members published a document called "Zero COVID-UK : Why is England not pursuing an elimination strategy?"

The stated objective is "a new overarching strategic objective of achieving a Zero COVID UK, i.e. the elimination of the virus from the UK"

This is effectively copying New Zealand, for the very good reasons that were set out in the document.   But I am a pragmatist, and the report ignored two important issues:
  • New Zealand's subsequent experience with imported infections
  • The UK's proximity to continental Europe and Ireland, and consequent much higher rate of visitors and returning citizens
In the UK we need to find a way of living with the virus, whilst getting life back to as near normal as possible.  ZeroCOVID as StrictZERO is impractical.


#NEARZERO

NearZero is:
  • Aiming for zero, but realising that is not feasible in practice
  • Establishing a target level of infection for the country that reduces the risk of catching COVID-19 to a level that is bearable by comparison to other risks in life
  • Translating that target level into a target for each local area, above which threshold extra action is required
  • Having mechanisms to quickly identify any local outbreaks that exceed that target
  • Having systems in place to pounce on such outbreaks to bring the local rate down below the target
  • Having a way of living that helps to keep infection rates low
  • Minimising new cases coming in from abroad, be that visitors, returning citizens, or goods


Target Level of Infections for the Country

The target level needs to be below where the UK is today.  Currently the more difficult areas of society are not yet open, and infection rates are continually threatening to put specific industries or whole areas of the country under lockdown.

Pending further debate my proposal is this.  Back in early May it was reported that Professor Chris Whitty had advised ministers that a 'very low' infection rate of 1000 new infections per day nationally should be the target.  That is equivalent to about 2 new infections per day per hundred thousand people.

That seems a reasonable level to be the target if spread evenly over the country, whether that is England, other parts of the UK or indeed any country.

It has previously been estimated that people would be out and about infectious without realising it for around five days.  For a town like Watford as an example, with around one hundred thousand people, that would mean around 10 people out and about infectious.  I could live with that in most situations.

However we have already estimated that at current testing levels, the real number of infections is at least five times the "new confirmed casas" figures that are published by Public Health England.  Tests on people with symptoms misses many others.

So we ought to be aiming for a national total of around 200 "new confirmed cases" a day, equivalent to 1400 per week, at current testing levels.  The current level is a 7-day average of 1812 cases per day and rising.  At least nine times too high already:

Setting a Threshold for Each Locality.  A Way of Living

However when outbreaks occur, they can get to serious numbers quickly because people are infectious before they realise they have contracted the disease.  A single outbreak is typically hundreds, whether that is in a meat processing factory or indeed the outbreak in Auckland New Zealand, which was spread more widely in the community.

When some parts of the Uk are experiencing outbreaks that put them way above the national target, that means other parts of the country need to be better than the national target.  

It only needs one person to start an outbreak.  That still makes large gatherings risky, and the risk remains of outbreaks in food factories, schools and other workplaces.

In effect each locality needs to be aiming for zero, with the first sign of trouble being pounced on.

We need a vaccine, or some other way of reducing transmission.  In the meantime we need to continue with social distancing, masks and face coverings, and hand hygiene.  (Note the Oxford comma, this being written in Oxford.)

Local wardens around the country advising the public, and if necessary chastising them, would help.  Such people are now beginning to be deployed, albeit under the name of "Covid Marshals".  Perhaps doubling as contact tracers if there's an outbreak.

Pouncing on Outbreaks

We recently had portable test stations set up behind a supermarket in Oxford, when the city was declared at "Amber Alert".

Testing needs to be wheeled in to any other local outbreak, but at the first sign of trouble.  That's together with 'boots on the ground' tracing, and support for those people instructed to self-isolate.

But that lower threshold means such an approach is only practical when the general infection rate is very low, #NearZero nationally and aiming for zero locally

Identifying Outbreaks

Identifying Outbreaks is a tricky aspect.  Current testing methods primarily rely on people displaying symptoms, which has meant they have already had the opportunity of infecting other people.  By the time the statistics are reported, the data is nearly two weeks old.  That's two weeks lost in intelligence.

Faster methods are clearly required.  The ONS Infection Survey is being expanded, but will only ever provide a general rate of infection, not identify all specific cases.

Testing of viral RNA in effluent is happening, and could be very helpful if testing is of every effluent stream.  But it is not clear how quickly RNA gets into people's number twos.

A cheap, immediate test is needed.

Minimising new cases coming in from abroad

This is extremely difficult, as New Zealand has found despite its very strict policies:
  • For visitors and returning citizens
  • For physical goods, especially colder ones where the virus may last longer in or on them
Leaflet when tested

Airports and sea ports need testing procedures on arrival, and preferably an international agreement of a way to do this before departure.

Fast cheap methods are needed.  The issue is temperature and other checks won't identify people who are pre-symptomatic but infectious.  One possibility is to use sniffer dogs, such as are used for drugs at entrances to music festivals and other events. Training has already started.




HOW IS #NEARZERO DIFFERENT FROM THE OTHER ZERO STRATEGIES?

There are of course strong similarities, but two key differences:
  1. Attitude.  A recognition that COVID-19 is not as serious a disease as MERS, that there will outbreaks, and that a very low level of infection is a more pragmatic balance between the risks of COVID-19 and the 'costs' in every sense of the counter-measures 
  2. Counter-measures.  These should be proportionate.  Full lockdowns are not needed when there are individual outbreaks.
However, should SARS-COV-2 (SARS2) mutate into, or be followed by, a SARS3 or SARS4 that is as murderous as MERS, then New Zealand's StrictZero will be needed.


GETTING TO #NEARZERO

Clearly the rise in infections in the graph above is showing the current approach isn't working.  This can only inherently get worse as people head indoors as the weather gets colder.

I had previously suggested that a second lockdown should have happened earlier in the summer when the infection rate was closer to the #NearZero target.  In theory that approach could have reduced infections to a sixth of the current level in only three weeks.

That option was apparently considered by HM Government, but rejected.  'Hoping for the best'.   Now it will take longer.  Unless another approach can be found.  Suggestions please.

Update 9/9/20: The UK Government has imposed new restrictions from 14 September for Engalnd, ostensibly to avoid a second lockdown.  But will these only stop infections increasing?  We need measures to get infections right down to very low levels.


THE SWEDISH ALTERNATIVE

A lot of people are suggesting doing the opposite and relaxing restrictions as in Sweden. This option is examined and provisionally rejected, for the UK at least.   


IN CONCLUSION

StrictZERO such as ZeroCOVID is not a practical proposition for the UK for SARS2.  But getting to #NearZero will provide significant benefits, including unleashing the economic recovery we need. #NearZero is a more pragmatic approach than ZeroCOVID, albeit still difficult.  #NearZero will need:
  • Policies in place to support #NearZero once achieved.
  • Steps taken to achieve #NearZero.  UK infection cases are rising.  Any further delay will make it more difficult.  The new restrictions in England from 14 September may not be enough to reduce infections, only stop them rising exponentially



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