The UK started its first Lockdown in March. Wales started a short FireBreak in October. England recently started a second national Lockdown.
We know that any set of restrictions has detrimental effects, which I identified back in August. People are rightly concerned about lockdowns. So why might a Lockdown or FireBreak be needed, and how long should it last?
WHAT ARE THE OBJECTIVES OF LOCKDOWNS AND FIREBREAKS?
COVID-19 is highly contagious. People become infectious before they display symptoms. The natural R number is 3, in that one person will typically infect another 3 people. That is before they typically have to take to bed and thereby stop infecting others outside their household.
Whilst R does not tell you timescale, the number of people infected each day by COVID-19 can easily double in a matter of a few days if measures against transmission are not adequate. 1000 people quickly becomes 2000, then 4000, then 8000, then 16000 etc. As a proportion of people require hospital treatment, of which many die, that can quickly mean hospitals can become overrun such as was seen early in the year in Italy.
Social distancing, masks and washing hands can help to reduce transmission. But we have been finding that people do not do enough to stop infection rates increasing, especially as the weather has cooled and people spend more of their time indoors, where transmission is more likely.
The first objective of a lockdown is therefore to slow the growth in infections so that:
- Hospitals are not overrun
- Deaths are reduced
- The incidence of LongCOVID is reduced
Stopping daily new cases increasing means getting R below 1, or more usefully by getting the daily growth rate below zero.
But it is only by getting the daily growth rate well below zero that infection rates fall and the economy can start to re-open.
That is the idea of vaccines, to reduce infection rates to such a low level that normal life can resume. That is what is done for influenza. It has not gone away, and some 10,000 people a year still die as a result (from 7,000-21,000 in the UK in recent years, according to Professor Whitty in the press briefing on 21 September). We might expect that sort of situation to be the ongoing case for COVID-19 with a vaccine.
But Lockdowns and FireBreaks can similarly get infection rates low or very low, and thereby allow the economy to re-open in part or in full. That is the second objective. Which the UK Government seems to ignore. But should not be forgotten.
THE FIRST NATIONAL LOCKDOWN
Here is a graph of what happened in the first national lockdown in March and April 2020:
The lockdown took a few days to take effect, but over the following three weeks the daily infection rate dropped by some five sixths from the peak. There was only a small further improvement in the following week. So most of the improvement was achieved in the first three weeks.
THE FIREBREAK IN WALES
Wales started a 17-day FireBreak on 23 October, as schools were breaking up for half term.
Analysing the available data in detail, the overall effect was to reduce the infection rate by around half, but more in areas of high infection. As reflected in the ZOE King's College Symptom Study data:
The improvement was not as good as the original national lockdown, for three likely reasons:
- It was 17 days not the full three weeks. Although that only accounts for a small part of the shortfall
- Restrictions were not as stringent as the original national lockdown. For example, most school age groups in Wales were allowed back to school after half term. School transmission is as much about adults as kids - the parents of younger children meeting up with other parents, and teachers and other staff mingling.
- People are becoming increasingly bored of the restrictions, with some arguing against them and undermining them
THE LATEST LOCKDOWN IN ENGLAND
The first lockdown never ended for the entertainment industries. Nevertheless the latest national lockdown in England is known as Lockdown 2, running from 5 November to 2 December.
This has been set for four weeks, but lighter than the original lockdown and the Welsh FireBreak. For example schools staying open throughout.
Symptoms will typically show around five days after infection, so statistics based on symptoms would be expected to show the effect of the lockdown from around 10 November. It's still a little too early to get any clear picture.
However the COVID Symptoms Study run by ZOE and King's College London is beginning to show the effect. So far infections have stopped rising in each main area across the country, but there's been little improvement:
In particular:
- North West and North East England have continued the decline shown as a result of the tier 3 restrictions
- South west is showing a useful reduc tion
- But little improvement in other parts of the country, with South East still increasing
BACK TO FIRST PRINCIPLES
Ian Jones , Professor of Virology at Reading University stated on BBC Radio Oxford breakfast show last Thursday 19 November breakfast show (at 3hours 32min25s) that "If everybody could live for the next month three metres apart.... the virus would become extinct. There's no doubt about that. "
That can be explained with the virus's lifecycle, as follows:
- People tend to show symptoms between 2 and 17 days after infection, but typically after only 5 days
- People become infectious before showing symptoms and remain infectious for some days after showing symptoms.
- People will tend to infect their own household, likely within the first few days of becoming infected
- If people and their household were to self-isolate as soon as they believe one of them has been infected, they and their household would no longer be infectious after about three weeks, certainly by a month
- If everybody in a geographical area was to simultaneously self-isolate for a month, nobody would be infectious and the virus would be eliminated in that area.
- Indeed three weeks would be enough to virtually eliminate the virus in that area
Unfortunately not everybody would be able to self-isolate for three or four weeks. Hospitals, care homes and some other organisations MUST stay open regardless, and staff will need to continue to go to work. Some people would not be able to store enough food for that period.
In the first lockdown supermarkets remained open. Hence the lockdown did not achieve complete elimination in the first three or four weeks. A Lockdown or FireBreak can only be as effective as the level of restriction on people meeting others.
That suggests that if as many people as possible were to self-isolate simultaneously for three weeks, more stringently than in the first lockdown:
- Infection rates would drop by at least the amount achieved in the first lockdown
- Infection rates should drop to #NearZero levels, allowing much of the economy to re-open, plus a host of other benefits:
IN CONCLUSION
If the objective is to simply avoid the NHS from being over-run then only restrictions equivalent to the current national lockdown in England are needed. But these are not very effective, so will be needed for a significant period of time.
If the objective is to re-open the economy, and minimise the harms from a lockdown, then a short, sharp FireBreak is needed:
- Short like in Wales, but for a slightly longer period of three weeks
- With sharp restrictions:
- Like first national lockdown to achieve a substantial reduction in infection rates across the country
- Even tighter restrictions to get to #NearZero to let most if not all of the economy re-open. Restrictions should only be to allow absolutely vital businesses and organisations to stay open, whilst encouraging people to self-isolate
Education of children is important. But currently many schools are having to close or send pupils home. That disruption can be avoided if an investment is made in a short, sharp FireBreak with schools closed, except for children of vital workers.
When? That will be discussed in this blog once the Government's plans for December are unveiled tomorrow.
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