31 July 2020

IF ONLY JOHNSON’S GOVERNMENT HAD LISTENED

On 11 June, the Financial Times kindly published my letter I wrote a couple of days earlier, right,  with a suggestion to “save the summer”.

Local restrictions have now been imposed across much of northern England and the Midlands, tomorrow’s easings for 1 August have just been deferred, and holiday quarantine has been imposed on Brits returning from places such as Spain.

So it’s worth revisiting that letter and the thinking behind it.  Are the ideas in it still relevant?

I should say first that I hate lockdowns as much as the next person.  But as shown in this posting , it is a tactic of last resort when other tactics are not enough, and is available to be used when needed.

This is the letter:


In keeping the letter short, I had to omit much of what I was thinking.  This posting lets me fill in the gaps, which you can see me saying if you go back to the @COVIDCourier tweets from around that time 

The title was “A lockdown plan to save what’s left of summer

People are now looking ahead to the winter, given that being indoors more will put more pressure on the infection rate.  But I saw, and still see. the challenge as being far sooner, over the summer.

The introduction “Your report ‘Exhausted frontline doctors fear second peak’ (June 9) is yet another reason why we cannot take the risk of a resurgence of the virus. A second peak would mean more deaths, more financial damage and more heartbreak.

The government’s “Protect the NHS” strategy is about not over-running the NHS.  It is NOT about saving life.  No surprise that the ONS has now reported that excess deaths are far higher than any other country in Europe.  England’s strategy is ‘flu thinking’ not ‘SARS thinking’, the virus behind COVID-19 being SARS-COV-2, related to the original SARS virus.

The letter continued “A second lockdown would be unavoidable to contain it [a second peak]. Why wait? We’ve already seen the damage that delaying a lockdown causes by being too late. With R [number for] transmission, now hovering around 1.0 in some regions, and hospitals such as Weston-super-Mare already overrun, do we really want a summer like that?

Discussion in the last week or so has been whether lockdown on 23 March should have been on 16 March or earlier.  The near-universal agreement is full lockdown at least a week too late, causing thousands of avoidable deaths.  The regional part  meant do we want to live under the threat of local lockdowns, through the summer and beyond?  Dependent on region, R has remained around 1.0, just below, or indeed above.  Here are the latest figures:

The letter continued “By locking down now and aiming for an R of 0.5 the maths says we would be down to nearly no new cases by the end of June or early July. Then we could open the economy while adopting the best possible anti-transmission techniques to keep COVID-19 at bay. Indeed, that is the only way to save the summer.” 

That is according to this graph:


It has since been shown that the lockdown had an R value of 0.57, and achieved a five sixths reduction in daily infections before levelling off.  A more detailed discussion of of R and the R-based Change Factor is given here.

To get new cases down to near zero, only a second lockdown would get R down low enough to get infections down quickly enough.  The justification for a second lockdown was fourfold, and still is :
  • The sooner we can get new cases down, the fewer deaths would occur.  With the extra advantage, as it turns out, of reducing those surviving but suffering from masty LongCOVID symptoms for months, which some people think will be a bigger problem than deaths [links to follow]
  • Very low cases means greater public confidence for people to go out, needed for the economy to recover, and to send their kids back to school
  • On timing, a large set of lockdown easings was slated for 4 July.  A very low level of infections would have made it safer to make those easings.  They went ahead on 1 July, but that was too early.  No surprise new infections immediately increased, so now the 1 August easings have been deferred
  • Timing was also in the context of state schools breaking up around 17 July, and private schools a week or so earlier. Finishing the lockdown  by early July would have saved the tourism industry here and abroad
Indeed my concern was that holiday destinations like the Spanish Balearic Islands, that had achieved a near zero level of infections, would refuse to accept British tourists unless the UK infection rate was much lower.  Ironic then that it’s the British government that has caught the Balearics up in a blanket two-week quarantine for Brits returning from Spain.  Unfair and inappropriate.  So watch this space.

I was also concerned that staycation areas such as the West Country and Lake District were already sending out distress signals that they feared being overrun by infectious guests from other parts of the UK. Might the police even be forced to close the main roads into these and similar areas?  That could still happen.

It is still possible to do a second lockdown, but:
  • With cases now rising, the longer a lockdown is delayed, the higher the infection level at the start, and the longer a lockdown would be needed.
  • If done before schools go back in September, the lockdown would be needed in August, and disrupt the summer
  • If done any later, infection levels would be too high for schools to go back.  Remember schools are more about the adults than the kids.  Teachers, other staff and parents in close proximity. Plus kids taking infections home – which hasn’t yet been ruled out – especially dangerous for multi-generation households in which older folk are more at risk of death
The Independent Sage group , which consists of former SAGE members and other senior academics, are recommending:
  • A ZeroCOVID strategy, or “TowardsZero which is what Ireland and Scotland are already following.  That is aiming for zero, getting down to no more than 1 new infection a day per million population. and dealing with any local outbreaks. Or preferably 1 per day per region, meaning 8 for England per day.  So #NearZero . PM Johnson today reported ONS now estimate 4200 new infections a day in England, equivalent to 76 new cases per million.  Far too high, when Scotland and Ireland are already each down to a mere handful of new infections, and consistently reporting zero daily deaths                 
  • In which they support my contention that such a strategy would “allow all social distancing easures to be lifted, schools to be fully open, the hospitality and entertainment industries to reopen fully, revitalisation of the economy and a sense of much needed normality for the population"
  • Achieved by boosting the NHS Test and Trace service to a far higher level.  But being academics that overlooks that in practice this is unachievable in effectiveness, timescale and cost.  So a lockdown as I have suggested is the only reliable solution.

IN CONCLUSION

England’s strategy of allowing COVID-19 cases to be as high as the NHS can handle, without adopting a Near Zero strategy. is preventing England getting back to normal.  It is perpetuating a level of infection in every region of Engalnd that is too high and means local lockdowns, delayed easings, and is putting at risk the objective of getting schools back safely in September.

The need for a "Near Zero" strategy is endorsed by Independent SAGE, which they call “Towards Zero” and “Zero COVID”.  But it is impractical to scale up the Test and Trace service adequately, as they suggest, so the only reliable mechanism is a second lockdown.  That is still relevant.

Today PM Johnson suggested a further lockdown is a possibility.  The government needs to bite the bullet and do a second national lockdown now.  Compensating businesses as necessary.  Though as outdoors is far safer than indoors, preferably allow pub gardens and outdoor cafes to stay open.  We need something to enjoy!

28 July 2020

COVID-19: OUR FIGHTBACK OPTIONS

We know that COVID-19 is caused by a virus called SARS2, officially SARS-COV-2.  Each virus is so small it cannot be seen using standard microscopes, but can only be seen under an electron microscope, as shown to the right. 


Each virus consists of:
  • A fatty coating
  • RNA inside
  • Protein ‘spikes’ that bind onto ACE2 receptors on human cells to inject the RNA, which then hijacks the cell’s mechanism to produces more viruses, thereby killing the cell

Viruses aren’t ‘alive’ as such, and can’t be ‘killed’.  But they can be rendered inactive.


WHAT DOESN’T WORK

Firstly it is important to realise viruses are not bacteria, and so:
  • Anti-biotic drugs don’t work, though may be deployed to address a secondary bacterial infection
  • Anti-bacterial hand wash and other products do not work, unless they contain at least 60% of an alcohol by volume (slightly less by weight)
  • Disinfectants that are not based on bleach will not necessarily work

WHAT DOES WORK

There are fundamentally five ways to de-activate SARS2:
  1. The body fights viruses such as SARS2 by using the proteins in anti-bodies, T-cells and cytokines to bind with the spike proteins, thereby rendering them inactive
  2. Various ways to break up the fatty layer, thereby rendering the virus inactive
  3. Destroying or modifying the RNA
  4. Reducing the chance of transmission from one person to another
  5. Medicines and medical techniques to reduce severity of the symptoms

USING PROTEINS AND VACCINES

Although the body uses proteins of various types to bind to bind to the spike proteins of the SARS2 virus, I am not aware of any artificial method that uses this approach.

Though vaccines work by stimulating the body to produce anti-bodies, T-cells and cytokines in advance of infection to either:
  • Prevent infection
  • Reduce the effects of infection

BREAKING THE FATTY LAYER

Someone can become infected by touching their mouth, nose or eyes with hands that have viruses on them.  They could have touched a contaminated surface. So we want to make viruses on surfaces inactive, one way being to break the fatty layer of SARS2 on surfaces:
  • Hands
  • Any surface that would be touched, be it worktop, door handle, cricket ball etc.
Like any other fatty substance, soap and water is universally regarded as the best way to clean hands, by breaking down the fat and flushing the viral remnants away.  Here is the NHS advice


Alcohols disrupt the fatty layer, and so hand sanitisers with at least 60% alcohol  can be effective.  But not other hand sanitisers.  "Which?" has produced a guide.
For other surfaces, disinfectants can be used. 

The World Health Organisation recommends simple bleach, to be applied by cloth rather than spray.


For businesses such as in food preparation, there is specialist guidance available:
This research was published in  the Lancet in early April, showing which ddisinfectants work (soap working immeidately for 2 out of three samples). 

It also shows how long the virus survives on various surfaces.  Hard surfaces like steel and plastice lasting several days, whereas paper only a couple of hours. Bank notes look a risk at 2 or 3 days.


It is important to realise that alcohol and disinfectants should not be taken internally.


But it is disappointing that it is not safe enough to have a puffer with a soap solution that could be used after infection.  Sadly that would also be dangerous.


DESTROYING OR MODIFYING THE RNA

DNA and RNA, including viral RNA, can be affected by UV light.

For humans it is dangerous, and can for example lead to skin cancer or eye damage.  Hence sunglasses being marked as UV safe.

What about the RNA in the SARS2 virus?

The most powerful UV rays of shortest wavelength, known as UVC can work.  Typically a wavelength of 254 nanometres (UVC254) is used to disinfect surfaces  such as buses, as that avoids liquids and staff to apply it.



REDUCING THE CHANCES OF TRANSMISSION

The key problem with COVID-19 is that people are infectious without realising it:
  • Either before they develop any symptoms, for a few days or longer (pre-symptomatic)
  • Without developing symptoms for a longer period (asymptomatic)
There are various ways to reduce the chances of transmission:
  • It is believed that transmission is principally through viruses on water droplets in the air, so:
    • Best to be outdoors or in well ventilated indoor areas
    • Social distancing.  Most water droplets drop to the ground within  about 1 metre, unless someone is laughing, breathing hard exercising, coughing or sneezing.  Risk is significantly lower at 2 metres:
      On pain of death
    • Transparent barriers, such as being used in supermarkets between checkout staff and customers
    • Wearing a mask (see separate posting, to follow):
      • PPE grade, often called N95, that protects the wearer
      • Simpler masks and face coverings for “Source Control” that stop most droplets on leaving the mouth, and therefore stops them reaching anybody else.  “My mask protects you. Your mask protects me”.  The better masks provide some limited protection for the wearer
    • Visors to provide protection for the wearer and those being breathed upon, such as worn by hairdressers.  Visors should always be used with a mask, as droplets can escape around the sides of visors
  • Reducing the times someone touches their mouth, nose and eyes.  People unwittingly do so over 20 times per hour ordinarily
  • Washing hands, as above
  • Cleaning potentially contaminated surfaces, as above
  • Lockdowns, as below

LOCKDOWNS

A “lockdown” is a ‘blunt instrument’ that reduces transmission by stopping people from meeting, principally by getting people to stay at home and restricting how they can meet people from other households.  This can be:
  • A formal hard lockdown, as used in Spain.  People weren’t allowed out, involving severe restrictions even on food shopping
  • A formal less hard lockdown, as used in UK.  We were allowed daily exercise and food shopping
  • A voluntary lockdown as used in Sweden, where schools and most businesses stayed open.  If properly explained to the public, that can be nearly as effective as a formal lockdown, with Sweden finding travel dropped as much as in neighbouring countries that had a formal lockdown
Lockdowns can be national or local.  The UK has had its first major local lockdown in Leicester, having had smaller lockdowns in individual factories, hospitals etc.

Lockdowns can be used in two ways:
  • As last resort, when other measures are not working and infections are rising.  This was the case in the UK.
  • As first resort, to prevent infections taking hold, as used by New Zealand
Which way is dependent on each countries’ circumstances.  Islands with little external interaction, such as New Zealand, have benefited from the ‘first resort’ approach.

Whereas the UK is more open to international travel. and so followed a ‘last resort’ approach, given the substantial ‘side-effects’ of a lockdown:
  • Restrictions on people’s lives
  • Adverse impact on mental health
  • Adverse impact on the economy, affecting jobs
  • Adverse impact on the national debt, with need for increased borrowing or other fiscal measures
Lockdowns are very much a matter of ‘horses for courses’ and a matter of judgement.


MEDICINES AND MEDICAL TECHNIQUES

Whilst reducing transmission is clearly the best way to reduce the level of illness, at least until a vaccine is available, how about those people who have contracted the disease?

Looking at the basic process for how an infection affects someone [link], the obvious thing to do is to reduce the chances of them either:
  1.  Needing hospitalisation
  2. Being affected by LongCOVID, where there are prolonged symptoms, often due to organ damage
Sadly the treatments that are available are almost exclusively in hospital.  That’s medicines, for example to stop microclotting or the use of equipment to help breathing such as CPAP machines (air pumps) and mechanical ventilators. 

There’s virtually nothing available today for the two objectives of helping people at home.  Certainly no medications, now hydroxychloroquine has been debunked as ineffective yet can kill.

There is the usual advice for flu-type infections, such as bed rest, plenty pf water and paracetamol .  There is only one other technique for home use, to my knowledge.  That is deep breathing


IN CONCLUSION

The main hope against COVID-19  is that vaccines will be produced that are both safe and effective.  But that will take months, into 2021 at least, especially to ensure they are safe enough for mass vaccination.

Should medicines come along that could be taken at home to prevent serious illness, we could potentially be more relaxed about contracting COVID-19. 

But in the meantime, as death and LongCOVID makes COVID-19 such a dangerous disease, we need to adopt a mix of anti-transmission techniques:
  • Social distancing, preferably 2 metres
  • Face masks where 2 metres is not practicable
  • Other physical barriers, such as visors and transparent screens
  • Avoiding touching one’s mouth, nose or eyes as much as possible
  • Hand washing using soap or high-alcohol sanitisers
  • Treatment of touchable surfaces using soap, alcohols, disinfectants and UV light (none of which should be used internally)
  • National and local lockdowns as last resort if infections are rising, or to get infection rates much lower (see separate posting)

27 July 2020

COVID-19: GETTING ADVICE. THE GOOD, THE BAD AND THE FRANKLY UGLY

COVID-19 is a nasty disease.  Not only can it routinely take us out of action for a week or more, we can end up hospitalised, dead or with LongCOVID.  That’s serious ongoing symptoms, whether we have had initial symptoms or not, whatever our age.  Further details are here.

Obviously we want to reduce the chances of catching COVID-19.  Or of giving it unwittingly to family, friends and others.  Especially as we may not show symptoms for 5 days or more, if at all, yet still be infectious.

So where do we turn to for advice?

I was about to write about hand sanitisers, so I keyed this search into Woggle “COVID BEST WAY TO WASH HANDS” and then “COVID HAND SANITISER”.  As any former boy scout would.  Be prepared.

Every country has its own advisory web pages, for the general public and then for businesses, such as the UK’s Health and Safety Executive.  The searches not only found the specific information, but unlocked the broader advice provided by each entity.

As a general rule I was disappointed, often bitterly.  Unclear, incomplete, yet too much verbiage with little use of graphics or videos.

Let’s look at some of these web sites in turn.

Bear in mind that these web sites do not always agree with each other, such as on testing and the use of face masks.  In writing the other posts for this blog I will have looked at each of these sites, and attempted to unravel the inconsistencies.


WORLD HEALTH ORGANISATION

The WHO’s objectives are primarily to influence “public policies” at national level throughout the world. 

But they also have a limited section for the general public,  including this section on washing hands
How, but not why or when.  Nor any warning about inappropriate hand sanitisers:


Indeed they have prioritised alcohol-based hand sanitisers over use of soap and water.  The latter is cheaper, more readily available and all the other sources below argue better.

Sadly, this is why I regard WHO advice as only a starting point.  There’s better advice out there on a range of topics.


UNITED STATES OF AMERICA

Putting aside the way COVID-19 is spreading in USA, there is actually a lot of good advice available.  The problem is it’s being widely ignored.

The Center for Disease Control and Prevention (CDC) is one of the bodies that prefers the use of soap and water over the use of sanitisers.

Their hand washing advice includes the what, why and when. Though doesn’t explicitly explain which hand sanitisers are inappropriate. 

Here’s the CDC's COVID-19 sub-site.

There’s also the American "Family Doctors.org" .Some basics of hand washing.  A long list of when, but no mention of the importance of entering shops or other premises, to avoid touching objects with contaminated hands


NEW ZEALAND

New Zealand has been one of the most successful countries in eliminating COVID-19.  Their first case was as their summer turned into autumn.  So especially relevant to the UK now we’re nearly into August.  What is their advice to the public?

This is their advice for washing hands.  It includes a section on ‘soap versus sanitiser’ with the general preference for soap. But this web page sadly has no diagrams or videos.


Here is their COVID-19 website, covering not just the health aspects, but also  financial support and other aspects.


SWEDEN

Sweden has adopted a different overall COVID-19 strategy to the rest of Europe, by allowing schools and most businesses to stay open.  They have relied on a voluntary lockdown that has been almost as effective as statutory ones, but which they believe will be more long-lasting.  There’s no need for lockdown to be “eased”, and for people to then go mad as if it’s all over. Which is what we are seeing in places like Spain and indeed the UK.

This relies on educating the public.  Part of this educational programme is their extensive website.  All the relevant parts are in English 

There are differences from other countries’ advice.  They have put more emphasis on social distancing.  Hence my nickname for their website “No sex please, we’re Swedish”. 

The emphasis on social distancing means they do not recommend the use of masks.  They are concerned that masks will cause people to stop social distancing.  Whereas in England distancing is widely disregarded, so masks sadly have become necessary.

This page contains this advice “Maintain good hand hygiene. Wash your hands with soap and water for at least 20 seconds. If handwashing facilities are not available, alcohol-based hand rub is an alternative. The alcohol-based hand rub should contain at least 60 % alcohol” That’s 60% by volume, a little less by weight. Surprisingly there is no why or when. 

Few if any graphics and videos for hand washing nor throughout the website.  But isn’t this the video age?


THE UNTIED KINGDOM

The United Kingdom consists of four nations that are responsible for their own healthcare and COVID-19 strategy.

We therefore have 3 sets of sources:
  • UK entities, including individual government departments with a UK-wide brief
  • Nations’ medical agencies
  • Private sector and other independents, often across the UK such as the “Which?” magazine and website

gov.uk

The UK government also has an elaborate website

But the only mention  of washing hands is this at the top of the page “Wash your hands regularly
Come on guys, you can do better than that!  Surely?


National Health Service (NHS)


This is the hand-washing page, which explains how, when and why to wash hands.  There are graphics and a video, with the emphasis on soap.
Sadly nothing at all on the use of hand sanitiser.  Definitely “Could do better”


Health and Safety Executive (HSE)

The HSE is focused on businesses, many of whom have retail customers.  Here is their hand washing page.  https://www.hse.gov.uk/coronavirus/working-safely/cleaning.htm Again with an emphasis on soap, but:
  • no stipulation for the right type of hand sanitiser
  • no recommendation for the right types of treatments for work surfaces
  • no graphics or videos
I also separately found this page on “Choosing hand sanitisers and surface disinfectants...”, but I can only recommend it for insomniacs.  Not a single mention of alcohol.

This is all too poor, to the point of being dangerous.  From the safety specialists!    More than disappointing.


So the UK official web sites are frankly a disgrace as to advice on something as simple as hand hygiene!


NATIONAL WEBSITES

The national websites only do a partial job on hand washing:

OTHER UK RESOURCES

My search identified a number of other resources, including:

BBC Science Focus

A useful web page, but without explicitly discouraging the use of inappropriate hand sanitisers


“Which?”

This is a good web page, but somewhat over-complicated.  The answer to the question is simply the following, and what products do or do not comply:
  • Soap, or
  • Hand sanitiser with at least 60% alcohol by volume
  • Nothing else will do

CONCLUSION

I am bitterly disappointed by the low quality of the main resources available, to advise on something as simple as hand washing.  Especially the UK national websites.  Sadly this is representative of the sub-standard quality of the websites on other matters.

As to hand washing, whilst we are on the subject, not one resource covered all the basics adequately, which I would conclude are:
  • Wash hands with soap and water where possible
  • Hand sanitiser should be at least 60% alcohol by volume (a little less by weight)
  • Do not rely on other sanitisers, especially anti-bacterial.  COVID-19 is caused by a virus, not by bacteria
  • Supported by what, how, why, where and when.  Especially on entering any shops or other premises, to avoid touching objects with contaminated hands
  • Using graphics and videos, not just words
Is that simple list really too difficult?  So it appears.  On many other topics too.

This blog will endeavour to include postings that are comprehensive, filling in the gaps in official coverage, and attempting to resolve the differences between them.

26 July 2020

HERD IMMUNITY – A FALLACY, BUT... (Updated 11 August for CROSS-IMMUNITY)

The term “Herd Immunity” keeps cropping up.  People accuse the UK government of following a Herd Immunity strategy.

So what is Herd Immunity?  Is it relevant?


WHAT IS HERD IMMUNITY?

It's an unfortunate term likening people to herd animals.

It’s where 60-70% of a population acquire immunity to a disease, such that if someone is infectious, it becomes sufficiently unlikely they will encounter someone to infect that the disease tends to die out somewhat.
Herd immunity can be achieved by:
  • Vaccines
  • The illness itself

THE EFFECTIVENESS OF VACCINES

In the UK there is an annual programme of vaccination for older folk and certain others, but this is optional.  Most of the population do not get immunised.  So there isn’t herd immunity generally, though may reach that level in the group eligible for vaccination.

Nonetheless some 2,000 to 28,000 people have died each year from the complications of flu in recent years.

As noted in this introduction. persistent LongCOVID symptoms that effect all ages mean COVID-19 is a much more serious disease than flu.  Any immunity programme will need to cover vast swathes of the population of all ages.  A massive and expensive task, even if a vaccine is proven both safe and effective.

Obtaining the proof needed to vaccinate a large proportion of the population will take months. Initial indication of safety and efficacy by September, but we are talking well into next year earliest for mass vaccination.  Fingers crossed.


NATURAL HERD IMMUNITY


The Maths Has It

Simple maths suggests that it would take many years for infection to reach 60% of the population.

Taking England, with some 55 million people, that’s 33 million for 60%.  It would require some 90,000 new infections a day, with or without symptoms, to get to that level within a year.  At a more realistic 3000 a day, that’s 30 years.  Simply unrealistic.

Even that is assuming mild infections convey some immunity for a sufficient length of time.  Neither immunity nor duration are yet proven.

So it was especially concerning that Sir Patrick Vallance, the UK’s Chief Scientific Advisor talked seriously about the UK aiming for herd immunity.  This was back in early March, 10 days before the UK’s national lockdown  Key part is from 4min35, with the previous section setting the scene.  As a result of a vociferous backlash, the UK government had to quickly assert it was not following a Herd Immunity strategy.  Yet the suspicion has never totally disappeared.


BUT WHAT ABOUT PARTIAL HERD IMMUNITY?

Sweden has followed a different strategy from the rest of Europe.  Sweden has chosen to adopt a voluntary lockdown , which they believe to be nearly as effective as legal lockdowns, for two reasons:
  • In acknowledgement that COVID-19 is a long term disease requiring public sacrifice for long periods of time.  More sustainable to explain the reasoning, and get people to adhere to advice voluntarily.  For example travel has reduced as much as in neighbouring countries
  • To minimise the ‘side effects’ of a lockdown.  Schools and businesses have been allowed to stay open, with the exception of gatherings over 50 people and a few other restrictions
They’ve been able to stick with this strategy by keeping within their health service capacity, and explaining to the Swedish population that a higher death rate in the short term is to be expected, but will not appear so high as time goes by.

They insist this isn’t a Herd Immunity strategy, but have found a immunity bonus according to their chief epidemiologist, Dr Anders Tegnell:
  • Nobody tested positive for COVID-19 has had a recurrence (at 20min25s).  That suggests a level of immunity, but not yet clear for how long.  Six months is one estimate
  • Total cumulative cases, including where mild or no symptoms, could be as high as 20% or more in some places in Sweden (at 21min15 to 22m40), which confer immunity.  Though other areas appear very low. 
  • The levels seem to be enough on average across the country to noticeably reduce R, and make it easier to defeat some local surges
Update 11/8/20: But see notes about cross-immunity below for possible explanation of  high levels of immunity.

Sweden has been heavily criticised for higher death rates than most other Scandinavian and European countries, in the short term.   Although lower than some other countries like UK, that Dr Tegnell believes are inherently more comparable.  We’re seeing enforced lockdowns being released across Europe, and countries such as Spain now suffering a massive resurgence, Sweden’s “voluntary” policy looks as if it is already being better than formal lockdowns.

As we know that COVID-19 is likely to be more prolific in winter than summer, due to people being indoors more, the time to assess Sweden’s strategy will be each March, 2021 and 2022.  By then they may have been overtaken in deaths by other European countries, yet have kept schools and businesses open.  Only time will tell.

It will then be interesting to assess how much partial Herd Immunity will have helped them.


CROSS-IMMUNITY  (UPDATE 11 AUGUST 2020)

Evidence is mounting of cross-immunity , where it is hypothesised that immunity to COVID-19 has been achieved for those people who have had a coronavirus type of common cold.  The four such coronaviruses account for 15% or more of the incidence of common cold infections .  Cross-immunity would create higher levels of immunity to SARS-COV-2 than from it alone.


T-cells are an important part of the human immune response to infection.  Levels of T-cells that provide immunity respond to SARS-COV-2 are being found in around 50% of city populations and elsewhere where common colds are common.  T-cells are kept (or are continually produced) for many years.  They've been found in survivors from the original SARS 17 years later.  Though T-cells tend to reduce in number in older people,  That may explain why oldies are been more likely to catch COVID-19.

Antibody testing has identified around 70% of people in the UK having had COVID-19 without symptoms.  Or are these tests just finding antibodies left from the corona-based common colds/?  I suspect they are, as it seems possible that the 'soup' of IgG antibodies for each coronavirus is so similar as to overlap and thereby be indistinguishable to a test. 

This new study looking at T cells, though not yet peer-reviewed, found:
  • For people who have been confirmed as having had COVID-19; "Circulating SARS-CoV-2-specific CD8+ and CD4+ T cells were identified in ∼70% and 100% of COVID-19 convalescent patients, respectively"
  •  For those who weren't confirmed as having had COVID-19: "...we detected SARS-CoV-2-reactive CD4+ T cells in ∼40%–60% of unexposed individuals, suggesting cross-reactive T cell recognition between circulating “common cold” coronaviruses and SARS-CoV-2."

In the latter case it is unclear whether those individuals could have had COVID-19 asymptomatically.  But the chances are these ae people who hadn't had it

So if around 50% of an area's population have had a coronavirus common cold, only 50% would be susceptible to COVID-19.  Then the 60-70% target for herd immunity to COVID-19 is reduced substantially.  Estimates are it would only need to take around 20-30% with COVID-19 itself..

That's the sort of level being found in Stockholm, Sweden for example, as noted above.  That would explain why Sweden's new cases have reduced so quickly.  Dr Tegnell was saying recently that he didn't understand why this happened, implying he wasn't relying on cross-immunity for the country's strategy.  So it looks like Sweden has struck lucky!


WHAT DOES THAT MEAN FOR EACH COUNTRY'S STRATEGY?

It is perhaps too early to rely on cross-immunity.    But it is certainly looking like the herd immunity concept might apply to coronaviruses as a set, rather than COVID-19 alone.

Hopefully we'll see infection rates dropping worldwide as that type of herd immunity takes effect for COVID-19.

If this happens in England, hopefully we can reduce or eliminate the need for local or national lockdowns.  But for now the experience in the north west, where infection levels remain stubbornly high, suggests we're not in that position yet.



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