COVID-19: HOW EFFECTIVE ARE LOCKDOWNS?

PM Johnson has announced a formal enquiry into the Government's handling of the pandemic, starting next year. 

Key questions will include 'How effective are lockdowns?', 'Were the lockdowns too late or too early?', 'How long, how tough?'.  Or as some people suggest 'Should lockdowns have been avoided altogether?'  This is either when the benefits of lockdowns are deemed to be less than the drawbacks, which as we know are considerable, or even whether lockdowns work at all.

To answer such questions, we must first understand how the virus transmits. 

HOW DOES THE VIRUS TRANSMIT?

It is clear that the primary method of transmission is through the air, together with touch.  This article recently published in the Lancet sets out ten pieces of evidence for airborne tranmission of viruses on water micro-droplets ('aerosols') that people exhale, which then float in the air.  This means the chances of transmission would be expected to reduce if people reduce proximity to each other, such as by the restrictions of a lockdown.

Otherwise there would need to be some other transmission mechanism, such as through the water supply.  There is no evidence of a credible alternative mechanism.

 

HOW MUCH DO LOCKDOWNS WORK?

To establish by how much lockdowns work, ideally there would be Random Controlled Trials comparing two identical populations with different lockdown restrictions.  Usually this isn't possible, but the Welsh 'firebreak' last autumn produced a reduction in infections by comparison to increases across the border in England.

Indeed in South Wales the firebreak from Friday 23 October to Monday 9 November produced a substantial reduction, followed by a rise as soon as the firebreak ended:

This clearly shows:

• Lockdown restrictions do reduce infections
• There is some lag between changes in measures before seeing a change in test results.  The combination of an incubation period of around 5 days, plus delays in testing.  That delay is important in considering how quickly the current lockdown can be relaxed, by needing to wait to see the effect of the latest set of relaxations
• Two weeks (and three weekends) is not long enough to eliminate the virus.  Its lifecycle suggests at least three full weeks, plus strict controls on visitors from outside the region
  

Fewer cases mean less hospitalisations and less death, and less cases of all ages suffering from LongCOVID.

WHAT EVIDENCE IS THERE THAT LOCKDOWNS DON'T WORK?

Conversely some people suggest there is evidence that lockdowns don't work. Here are over 30 papers showing the 'lack of efficacy' of lockdowns.  

The key distinction is between 'don't work' and 'lack of efficacy'.  The latter is to be expected given that it is impossible to totally eliminate contact between people such as in care homes, home care, food shops and their supply chain.  Indeed there were significant outbreaks during lockdowns in care homes and food factories, which spread in the community once staff went home. 

Reviewing the papers, there is a mix of conclusions, with some papers from very early in the pandemic, when evidence was limited.  Nonetheless the papers should be taken seriously.

One conclusion states "Our  study  suggests  that  efficient infection  tracing  and  voluntary  behaviour  is  more  important  than  actual  mandates  in  controlling infection, at least in the Danish context studied"  This was in regions of Jut.land, with differing restriction regimes.

Indeed context is crucial.  A paper on Belarus pointed out a far higher number of hospital beds per million compared to the UK which helped the response there.  

For the UK, I was hoping the nations of the UK could follow a similar low-intervention strategy to Sweden.  Again differences in the countries’ circumstances, such as culture and population spread, made the Swedish approach inappropriate for UK.

Context therefore makes it difficult to compare countries and areas within them.  It is nonetheless clear that the efficacy of lockdowns are limited, and are dependent on how and when they are actioned.   It is not realistic to say they do not work at all.

Whether the drawbacks of lockdowns outweigh the benefits is a separate question, covered here.  

 
RISK MANAGEMENT
 

Infections, deaths and LongCOVID are all of concern.  But what has worried Governments and their people most has been the risk that health services would be overrun, as happened early on in Italy.  This risk is seen as overriding any drawbacks of lockdowns.

It takes a few weeks for any action to have an effect on the need for hospital beds.  Action has to be taken in advance, taking account forecasts of likely and ‘worst case’ scenarios.

IMPLICATIONS FOR LOCKDOWNS

For the first few months there were no vaccines and little in the way of pharmaceutical treatments.  No reliable measures to reduce or treat infections.  That didn’t give governments much choice if they feared health services could be overrun.  Lockdowns were the principle option available.

The situation is somewhat different now vaccines are being rolled out, and some better treatments have been proven.  But the risk of health services being overrun has not gone away.  The new ‘variants of concern’ spread more rapidly (are more transmissible) and potentially outwit current vaccines.  The new variant from India is as yet poorly understood, and further troublesome variants are possible. 

So governments such as in England are right to unlock restrictions carefully, monitoring each step before going further.  

 
IN CONCLUSION

How effective are lockdowns?  Taking into account all the evidence, they do work in reducing cases and therefore hospitalisations, death and LongCOVID.  But how well is limited by how they are done, how quickly they are imposed and how long they last.  In the context of the specific country or region.