Friday, 29 May 2020

Immunity to COVID19 - Is vaccination the knight in shining armour?

Sars-Cov2-19
One of the few benefits of the pandemic for me has been my introduction to new methods of on-line learning and the expanding world of Webinars.

They might lack the personal touch of old fashioned meetings, but are good in so many other ways. No climate busting travel, no expenses, amazing ease of access  - and no-one sneezing over you!

I have listened, student like once again, to speakers from the world of immunology and MS discussing COVID19, virology, vaccination, immunity - all subjects close to my heart.  This is my report back.


Fighting infection - 

Our defences

As ever with immunology, descriptions of our natural defences against pathological invaders causes me to sit back in amazement and wonder! I'm not one for military metaphors, but it really is a battle between our immune system and the outside world with our white cells on the front line.

The very fact that you are reading this means you have overcome countless infections which have been dealt with by your defences. Bacteria, fungi, and viruses have to be highly specialised to overcome the obstacles put in their way. They are expelled by the mucus of a runny nose, inhibited by fever, hit by numerous biological weapons as they try to gain entry. Then they come up against the white blood cells. 

Our wonderful white blood cells
I won’t go into the mind-boggling details in this post (I will later) but suffice it to say for now that there are two phases to our reactions to COVID once they gain entry.

First, some of our white blood cells (right) behave rather like millions of micro-police officers (neutrophils and macrophages) who float around the blood looking for trouble, bashing trouble makers with their basic readily available equipment and the aggressive natural "Killer T-cells".

After that, they call up "back-up".
This is provided by lymphocytes and the others located in their 'stations' in the spleen and lymph-nodes. When called up, they work out who invaders are and if they have come across them before. Then specialised teams can deal with known culprits and process the details of those they haven't. New units of these lymphocytes are created to clobber invaders with some pretty impressive immunological weaponry specifically designed for each individual foe. As with severe COVID, they sometimes cause mayhem in the process, called the 'Cytokine Storm".

The reality of our immune defence to COIVD19 or any other pathogen is many times more complicated than any labyrinthine intelligence service, so the analogy ends there. Apologies to any immunology savvy readers who might gasp as this over-simplification. 

Yet that is the essence of our response to COVID19.


Vaccination


Measles
Vaccination is our attempt to get our immunological defences ready for the known culprits in our infection prone modern world, and was much discussed in the Webinars. Its recent achievements have recently been brought into sharp focus with the upsurge of measles following the Wakefield scandal; there were less than 50 UK cases of measles in 2003 before the scare and by 2009 the rate climbed to 1500. 

Indeed, the history of the world was changed by the BCG vaccine against TB termed "The Greatest Story Never Told" by one author. I am glad of the fact that so few of us doctors have ever seen a case of Diphtheria or Tetanus. I have never had to diagnose Polio though met quite a few who were disabled by this infection in their youth. I don't need much convincing as to the benefits of vaccination.

On to 2020 and much hope is naturally focused on a vaccine to COVID19, but first a further word on why this virus is such a problem and in particular why is it so infective?

Infectivity of COVID-19


If the virus overcomes your initial defences, and gains entry to your cells it starts using your own equipment in the infected cells for reproduction. It is able to turn your cells into fast acting photocopiers of itself. It then relies on you passing it on to as many others as possible. Being naturally gregarious and often crowded together, humans are good at this.

You might be aware, indeed sick of hearing about the R0 number. It stands for the Reproduction rate observed in susceptible populations. An R number less than one and the pandemic fizzles out.

What a sneeze can do.
COVID19 is highly infectious with its Ro number about 3. This compares to Ro numbers for measles of 13 and the savage 1919 flu outbreak of 2. Its main mode of transmission comes from people without symptoms shedding and share viruses. Travellers and others who meet lots of other people before isolating are termed super-spreaders.

The R number will fall as more people become immune either by getting the infection or by vaccination, then it becomes harder for the virus to find people with no antibodies which neutralise it..

Looking at it another way, human being's Ro number (called our fertility rate) is currently 2.4 with obvious resultant global over-population. Humans and COVID19 both spread very rapidly. 

Humans - the ultimate super spreaders 


So the virus is infectious. However, it only spreads only as fast as we can spread it. How quickly this happens on the global scale can be deduced from this map of our 1500 flights taken recently from satellites on a single pre-pandemic day. It is one of the ugliest things I have ever seen.



A map of car journeys in the UK would look pretty much the same. Add in mobility from train, bus, cycle and even foot and it all adds to the fact that as a species, we are super-spreaders. 

And therefore, in this modern hyper-mobile world:

Outbreaks anywhere = Outbreaks everywhere.

Unless that is, we do something. So how do we defend ourselves?

Our own immunity to COVID-19


Antibodies to COVID19.



Antibodies (in red) hitting their target
After initial uncertainly it now looks like we do develop immunity after infection with COVID19.

An early Chinese study 0f 170 hospitalised patients found antibodies in 100% of cases two weeks after infection. More recently researchers in Paris found 98% of hospital staff who had mild infections developed antibodies, when measured 40 days after the infection. Only one case out of 160 failed to do so. 

While much uncertainty exists about how long this lasts, this is good news. It means that antibody tests are useful at least over that timeframe and that immunity seems widespread after the infection.

What can we learn from SARS-Cov in 2003?

This was a similar 'sister' coronavirus responsible for the SARS outbreak in 2003. It was more severe, but less transmissible. Neutralising antibodies which protect against re-infection with SARS were found to last up to three years after infection, then declining.

If this happens with COVID19 it will be good news, but again right now we don't know for sure. Tracking antibody levels from blood or saliva tests with time will be give us more definite answers. 

Might immunity against other coronaviruses help?

Coronaviruses have been around for some time causing a range of milder illnesses such as colds and croup. It would be helpful is there was some cross-immunity against COVID19.

It seems that 30% of COVID negative blood donors were found to have some white cells which target the notorious spike protein, though at lower levels than those who had COVID19 infections and less completely too. This is really interesting and perhaps offers some hope that some of us at least have some anti-COVID19 weaponry already installed. 

As ever the authors are cautions, rightly so, it is however, very interesting indeed.


Hello herd immunity?


So is it a two horse race between the development of a vaccine and the acquisition of herd immunity through infection?

The only other horse in the race was lockdown, testing and tracing and suppressing the infection before it took hold, as has happened in South Korea and China. For this to work, the number of viruses out there has to be reduced to very low levels.

In the UK we stumbled at the first fence, stopping testing and tracing in Mid March and will now have real problems catching up. We simply don’t have the local infrastructure to do the work and perhaps even the political will to achieve it. 

So what does herd immunity mean?

This will ultimately be where we end up if 80% or so of the population developed immunity through infection or by vaccination. Though some sporadic outbreaks will continue, (see graph below as an illustration) the infection rate will fall and the pandemic eventually die out as the virus fails to find non-immune victims. 

Then they just wont to be able to spread from person to person. End of pandemic!  How far down this road are we ?

Herd immunity
In the high risk NHS hospital environment of Birmingham staff were screened for antibodies to COVID19. Only 20% of those with no reported symptoms and 40% of those who had symptoms have tested positive for antibodies. And that is with a very high level of exposure indeed.

Elsewhere in Europe 1-14% are reported as immune. In the UK, Public Health England recently found antibodies in 17% of Londoners and in 5% of people elsewhere. I suspect here in Devon the immunity is likely to be very low indeed my guess is about 2%.

However, right now, we have don't have a really accurate idea of how near we are to herd immunity or when we are likely to get there. These early indicators seem far from encouraging. 

The WHO have stated that any policy aimed at getting to herd immunity is dangerous, and looking at levels of immunity in the human herd so far, I certainly see why.

So it does look like we have some way to go right now to get to herd immunity. So what has been the effect of various types of lockdown on the development of herd immunity?

Lockdown lottery.


Sweden is a very different place from the UK, it is a huge country with a sparse well educated population of 10 million people and far less health damaging social inequality than here. 

They have taken a different approach to managing the epidemic, relying on social distancing, with a more far more lenient unenforced lockdown. They felt their approach was best for them without explicitly aiming for herd immunity.

Predictably they have had more initial infections with a higher mortality rate. Like in the UK, this has been particularly severe in neglected care homes.

But might this mean they will have less mortality later in the summer and next winter as they develop early herd immunity due to more widespread initial infection?

Disappointingly, early hopes for early widespread immunity seem not to be happening. Immunity in Stockholm has developed in just 7.3% of the population.

It seems even with by design in Sweden, and by accident in the UK, policies have led to  increased level of infection and mortality, yet we still have a long way to go to arrive at herd immunity. We have faced increased levels of infection and mortality without much of an advance in terms of herd immunity.

So is Vaccination the knight in shining armour?

Vaccination to the rescue?


There is an incredible amount of research going on in the world of vaccination and hopes of unprecedented international cooperation despite the many political obstacles 

There are competing approaches too. Some novel, targeting the genetic blueprint of the virus itself, RNA. Other approaches are more traditional. There remain lots of hurdles on the road to being able to get a vaccine from your local chemist.

The very earliest a vaccine can be expected according to experts is in the first quarter of the of next year and that is assuming success for the RNA vaccines which are simpler to manufacture and scale up. If this technology fails
A chunk of RNA
then vaccines developed with more tried and tested methods will be available later next year or early in 2022.  

Further, the mortality of COVID highlights the effect of ageing. With apologies to anyone past their immunological peak, myself included, this is called "immunosenecense".

Us old owls tend to fight infections less well. For the same reasons, we develop less of the protective antibodies the vaccine are intended to stimulate. Given the single biggest risk factor we have is our age, even a successful vaccine vaccine is therefore no panacea

Issues of global coverage of the vaccine in this global age also loom large. As I said earlier, outbreaks anywhere = outbreaks everywhere, so poor nations are going to need access to vaccines to help control the pandemic.

Yet if the challenges can be overcome and the problems of manufacture, delivery and administration are sorted, then a successful vaccine will accelerate our march to herd immunity and the end of the pandemic.

Soberingly, the chance of a successful vaccine arriving at all was guesstimated at 60%.

Consider this too. If it arrives next year, by then we will have had any summer outbreaks and whatever the winter might bring. We will have marched much further along the road to herd immunity by infection. Unless, that is we successfully suppress the epidemic by testing and tracing. 

The overall Webinar feeling was that a vaccine will jump on the tail of this pandemic after next winter and then possibly become a part of the annual vaccination program like flu for our many at risk groups.  It will become a normal part of life - endemic. 

Might we be lucky and COVID19 mutate into something less unfriendly?


Mutant COVID heroes??
Less unfriendly Sars-Cov2-19?


There was a bit of good news. Viruses do mutate, changing aspects of their proteins from time to time as they reproduce, rather akin to changing their clothes.

In general terms more severe strains cause more severe illnesses, and so people with the severe strains tend to stay in and isolate more effectively. This means there is an evolutionary pressure on milder strains to spread more widely and generate immunity without so much suffering. This too would help the pandemic to peter out. Perhaps. 

This was evident early in the pandemic in China. they isolated two strains, one far more severe initially accounting for 70% of cases, but falling in frequency as early as January as the less severe spread spread more rapidly.

However since then few significant mutations have been reported so Im not holding my breath, even if I am crossing my fingers.

Conclusion - The anti-pandemic recipe


After all that, I am left with perfectly understandable feelings of uncertainty.  However is it not a horse race between competing approaches and perhaps it will be a little bit of everything that ends the pandemic:


  • Suppression of the viruses ability to spread with testing, tracing and local lockdowns
  • The summer season reducing infectivity(at least in the north)
  • Increasing levels of our own immunity to COVID19
  • A lucky mutation or two.
  • Vaccination.
  • Time 

Two other things would make a big difference, and they, dare I say it..... a healthier leaner fitter population and better leadership. We really have made a dogs dinner of things so far (more on this later) and so continue with levels of infection which might well make another wave or two inevitable. 

So, while waiting for pandemic history to be written, I'll say it again....... use the summer to get fit for COVID19 - just in case.











Monday, 25 May 2020

COVID 19 - May Update.

As Einstein so famously said, making mistakes is human, to repeat them, insane. We do things, learn lessons, repeat what we do well and not what we don't. Ideally. 

Scale that up and we have this years experience with COVID to look at. We have different nations and different ways of managing the virus to compare, so it's time to scratch our heads and reflect. As ever, this is not easy. Humble pie is in the oven, cooking time uncertain.

Now that the data from COVID is piling in from all over the world, it's clear that rates of infections in the northern hemisphere are falling, though globally the pandemic rages on.  The NHS is reconfiguring again, this time to deal with the backlog of work built up over the first wave as well as people needing ongoing help with treatment and rehabilitation from COVID19.

So for us, perhaps that is the end of the beginning. Or is it?


Fattening curves.


Im afraid this isn't a typo. 

Here in the UK new cases seem to be running along at a stubborn 3,000 or so a day over here and deaths rates are slowly falling - our curves are flattening, but fattening too. 

Looking wider, we have not flattened the national curve in the way in the way we might have hoped for when compared to our continental neighbours. Have a look at the information from John Hopkins University in the US is you want more details. Their level of detail is incredible. 

Here is our graph, with the decline in cases far slower than the increase in March.

UK daily cases and 5 day average


Sweden have and even fatter curve, with worrying persistence of cases when compared to their Nordic neighbours. It looks like lockdowns matter!

Swedens daily cases and 5 day average




Italy, for one example have had more success in reducing overall deaths. These international comparisons reveal how much we have to learn.
Italy daily cases and 5 day average

There are big differences within countries too, in London cases are now falling, elsewhere they are increasing. The need for regional and local management is looking increasingly essential to deal with potential summer outbreaks and winter waves as well as the endemic phase thereafter.


Spanners in the works:


I have included cartoons to make reading this section more bearable.


Austerity

The ongoing impacts of slimmed down public services mean that any theoretical savings made by austerity have been dwarfed by their costs. In other words, investment in the future works. 

Our slimmed down local councils and public health bodies in particular have not been able to do the job they are designed for. Austerity was behind this, but also a politically driven  centralising of power unheard of till now. Our council budgets have been cut to the bone, even before the crisis they were struggling to fund their legal obligations in care and welfare to our children.


Without a shadow of a doubt, austerity has cost lives, created misery and cost money.


Advanced planning. 

Not because it wasn't done, but because good planning has been ignored. I listened to Jeremy Hunt last night revealing his take on the problem with planning. It is not, he said, that many of the recommendations of planing exercises were not acted upon but that they were designed for a novel flu virus and not for coronaviruses. 

This is unbelievably lame as we had already had warnings from SARS and MERS to alert us to the real dangers. Lack of sufficient PPE in the stores tell the story. Not cancelling big events like England Rugby, Cheltenham and footie matches (Liverpool vs AC Madrid would you believe) epitomises the delay in making the right decisions early. 


Get ready for lots of excuses. A little honesty, humility even, really would go a long way. 

Centralisation

Central diktats applied in blanket form to the whole country are sometimes necessary but local and regional voices have been marginalised by Chinese-style levels of over-centralisation. The situation in Devon and elsewhere is very different from London, decisions here would have been different too.

In a way all outbreaks are local and the marginalisation of local authorities and their capability to test and trace has made action on the ground difficult.


There will be reasonable calls for devolved power to the regions in the same way as in Scotland Wales and Northern Ireland. COVID19 gives this argument lots of ammunition.


Decision making

It sometimes seems that decision making has made on the hoof and entirely within Number 10. Delay, uncertainly and perhaps lack of urgency meant windows of opportunity were closed before the political curtains were even pulled back. 

We have to admit that "closing Heathrow" wont have been an easy call, but the needs were clear long before the decisions were made.

Flattening the curve is the least ambitious aspiration as compared to reducing the total numbers affected.

Messages on reducing individual risk have been absent.


Press briefings

For many of us, the daily press briefings have been a crafted balancing act between self congratulation and dutiful expression of grief. However, over-emphasis on back slapping and gratitude has detracted from objectivity. 

They might had had the function of lifting the nations morale but have veered too far towards becoming party political broadcasts with legal teams in the background yelling "Don't admit to anything!" 

I have lost count of the times I have heard the lines:

  • "Thank you everybody for doing everything"
  • "At all times we are following the science"
  • "We are going to flatten the curve"
  • "We have made the right decisions at the right time"

Most days I tuned in from the relaxed ambience of my greenhouse at 5pm. Yet even there my heart rate increased in frustration as I listened. Our high mortality, fat curves and slow decision making make confident assertions of success irritating. I have more than a niggling  worry that our response to future challenges will be compromised by inability to admit to recent mistakes.

The briefings had not even hinted that COVID19 risk factors can be reduced. Stopping smoking, reducing weight, eating well, exercising and getting enough Vitamin D would not only flatten the curve, but also reduce its height and thus overall deaths. 

The dramatic effect of poverty, social inequality and the impact on the BAME community are cans which have been kicked down the road. 

This was a glorious opportunity, with the nation attentive, to motivate improvements in health enhancing action and has been sadly missed.

Use of international comparisons only when they show the UK in a good light is particularly dishonest. 

The reality is more stark and with COVID19 as unforgiving as nature itself, these lessons need to be learned.


Late lockdown. 


Early lockdowns suppress the pandemic to low levels with manageable subsequent outbreaks. Late lockdowns work less well. There are questions being asked about whether our lockdown had any effect at all on disease trajectory at all. 

This all highly theoretical yet will be a feature of calls suggesting that lockdowns are ineffective and wrong, even if it could not be more clear they work well if done well. 

Even late lockdowns might be better than nothing, as can be seen by the low rates in regions like the South-West, even if the overall aim is to flatten the curve rather than making it smaller.


Testing and tracing in the UK 

This was abandoned at the worst time possible - Mid March.

Perhaps they realised the genie was out of the bottle, but you might be forgiven to thinking that this was the herd-immunity dogma in action: "Don't put out the little fires, let it go big and burn itself out"


Such nonsensical decision making is more likely with the pathological over-centralisation of  power in the UK. Ongoing testing and tracing would have continued to work well in areas less overwhelmed than London and even in the metropolis public sector services could have been rapidly developed if this was the decision at the time.

Now we risk repeating the same mistakes with over-reliance on unproven technology from our gadget-friendly health secretary, who seems too keen on risky novelty rather than building on current resources in the NHS and Public Health. 

Contracts are flowing to the usual private sector chums and donors who will take up the task of testing and tracing using low paid staff and off shore finance. Literally no change there.

The other practical concern is that once this pandemic is over, the testers will be dispatched and teams dismantled, losing the opportunity to develop built in public sector systems ready to go next time. 


Procurement 

Buying stuff we need has been at best chaotic and beset with cock-up's. 


The global scramble for kit might have made this problematical, but our stores of PPE were at inadequate levels, and some out of date due to cost and corner cutting. Again, over centralised decision making has shown its weaknesses, as has global supply lines and our own manufacturing short-fall.

One of the worst moments of the press briefings was the Home Secretary's pseudo-apology to PPE-light health care workers, the most basic mistake for anyone familiar with conflict resolution. "I'm sorry if you think you haven't had enough PPE".

The various cock ups amid the chaos are well described in the media, but at their heart lay poor preparation.


Care homes and carers. 

In our understandable haste to beef up the hospitals for the presumed onslaught, we missed out on looking after the most vulnerable in our institutions and those who care for them.

It might seem insane in looking back, but systems as they stood meant patients recovering from infections were sent into care homes while infectious. Infection was also spread by agency staff moving from home to home to fill in the many gaps opened up by self isolation of regular staff as well as usual recruiting problems.

The isolated nature of Care Homes is also highlighted by COVID19 as a big problem. Lack of a co-ordinated approach to or by them seems almost inevitable when you consider there are 5,500 different providers operating 11,300 homes in the UK. 

Along with lack of PPE and testing this led to excess and avoidable mortality.

In Plymouth many care homes have maintained a COVID free environment by planning way ahead of ponderous central diktat. It would be wise to ensure that all admissions to nursing homes are COVID free and discharges from hospital to sites offering intermediate levels of care to look after recovering COVID patients to ensure this. 

The Big Questions...


Did our lockdown make any difference?

The lockdown achieved its aim of preventing the overwhelming of health services, and it seems to have spared areas far from international transport hubs. But done late, it has not controlled the problem in the way we would have liked. 

It might also have allowed many vulnerable people to shield from risk and perhaps this is the main reason the health services have been able to cope. 

While denying that herd immunity was the aim, that is now in effect what we seem to be heading very slowly towards. 

Given to that the health services have learned fast how to manage cases and their own systems, we need to ask if an another national summer lockdown would be of any benefit. 

The long game is getting levels low enough to be able to extinguish local outbreaks. As we head for June, we are still not there as a nation, and certainly not globally, but lockdowns need to be done well to work. That means early and local.

Is next winter is the big issue?

Coronaviruses are generally highly seasonal, so the falls in infection rates we are now seeing might well be, in part at least, a feature of their biology as well as our response. 

Putting that aside, even if we continue with the current rate of 2-3000 new cases a day will mean that by the start of the flu season (October to May) we will have another 450,000 infected people in the UK which leaves us a long way from herd immunity and thus leaving most of the population vulnerable.

If we continue or repeat the lockdown into the summer, then we might reduce the number of summer cases, but also increase the number of people still to be infected when winter (and flu season) comes along. What then? Another rapid and more total lockdown? That will be difficult economically, politically and for the vast majority of the population.


What do we do now?


So Einstein was right. Let's not make the same mistakes again. 

The excellent independent "iSAGE" group set up to give advice truly uninfluenced by political pressure, have published recommendations on how to proceed from here. It's a long read and so a summary might be of use. Clarity will be wonderful in these times of uncertainty.

Ease the lockdown as soon as our capacity to deal with subsequent outbreaks is in place.

Restrict high risk activities like needless travel and control potential cases coming into the country. 

Reduce outbreaks by restricting large gatherings and maintaining physical distancing.

Protect at risk groups and keep them COVID free with the hope that a vaccine will come along, that treatment will be developed or that herd immunity will be achieved.

Protect care homes and crowded institutions They are a national priority and new isolation hospitals should be developed over the summer to ensure that our care homes, are kept COVID- free during the winter. 

Beef up public health. I'm worried that we continue to be dominated by our tech-heavy human-light over-centralised and heavily privatised approach. The list of cock-ups is increasing, driven in part by vain innovation alone instead of making the best of our present under-used and uncoupled public and primary care teams and networks.

Get ready for the winter wave  and assume we will have a nasty flu outbreak in tandem with resurgence of COVD19 from October through the winter. That means individually as well the health service and society at large. Planning needs to consider the worst case scenario

Develop better treatments and vaccines - hope for a vaccine is steadily increasing, but remains fraught with difficulty, there is a possibility it may never arrive. Treatments that make a real difference might be in the pipeline, but none have emerged as yet. (More on this soon) 

Globalise our response to future pandemics, that means a better EU and WHO as well as the many other networks developing out of the COVID experience. Much of this is happening in the science sector.


Well done.......


For anyone who has read till this point, well done! It is rather hard to keep this brief, but that has been my little overview of COVID till now. 

Hope for the best. This is a useful strategy to help us all keep sane in this ever more challenging world. It has been described by therapists as a good fall back position for anyone who is struggling with the many problems the pandemic has brought.  

Who knows, the best case scenario might happen, it might just die out in the summer.  

Worth hoping for, but not planning for.  


Tuesday, 19 May 2020

Is COVID19 seasonal? Will it just go away?

The most optimistic view of the pandemic's epidemiology is that it will simply peter out in the summer and disappear after effective lockdown measures have done their job. 

Alternatively, there are those who state that the lockdown has made no difference at all and that nature is following its course.

So I decided to look at whats been happening and find out, as best as I can, where the truth lies. First, some good news from the front line:

Good news from London


A recent study of health care workers in a London hospital shows that the decline there is steeper than elsewhere in the country. The the red line shows the number of COVID positive patients and the blue, the COVID positive staff (right axis) in that particular hospital.  The brown bars shows the total number of positive patients in greater London (Left axis).

So, rates of infection are falling in the community, the staff and in patients.

This is good news, optimists predict that at his rate there may soon be no new cases in London, though I suspect there will continue to be outbreaks. 


Epidemioloigy in London

Can this all be due to the success of the lockdown? I doubt it's the whole story.


So what is the effect of seasonality?


The seasonality of flu is self evident but that doesn't mean a different virus will behave the same way. Might a recent novel coronavirus outbreak in Germany give us a clue?

This graph show what happens to just such a novel coronavirus, a less disagreeable cousin of COVD19 which caused croup in Germany. It was called HCoV-NL63, and this outbreak took place during the winter of 2000. It clearly declined over March and disappeared by April.

COVID19 is far more transmissible and arrived here later in the winter, but you could argue that it might be behaving in similar way; fading out as the spring springs, the sun comes out and as vitamin D levels increase.



What coronaviruses tend to do


If COVID19 is behaving in anyway like this, then we could expect a natural decline at this time of the year. If true, this is also good news, but watch out for next winter. 


Comparing countries


Rates of infection are falling across all countries in the northern hemisphere. In some ways this might be what you would expect for a highly transmissible seasonal viral infection even without lockdown. The graph below shows the number of daily cases per million in the 10 hardest hit countries so far. 

I can't help but be struck by the similarities of the overall shape between countries, despite their differing approaches. Rapid increases, peaks in April and then variable declines. Interesting! 

 The dreaded "league table" is shown on the right side. 




In terms of daily deaths per million some differences do emerge, and the differences in outcome of different approaches become more clear, again the 'league table' is on the right. 


It seems to be that there are two things going on, similarities due to the natural history of the disease and different rates of control due to policy decisions.

If there is an effect of seasonality, the next place to look is the other side of the globe, as they enter their winter season.


What about Southern hemisphere?


The patterns here are worryingly different. The bizarre behaviour of Bolsonaro at the helm in Brazil is accelerating deaths there, but the rates do generally seem to be climbing as they approach their winter, so seasonality is important. The impacts will be different too, with many more young people, but far less capable pubic services.

Also evident is that early aggressive measures in South Africa, New Zealand and Australia seem to be keeping their outbreaks under control. Again, a mixed picture.




Global cases are sadly, still increasing. 

Seasonality, Social distancing and Lockdown


So as ever, the middle way seems to hold true; there is a definite effect of seasonality on the transmission of COVID19, social distancing and lockdowns have had effects too. For politicians to claim they have in any way 'beaten' COVID19 is nonsense, as is the claim the lockdown has made no difference. It's true to say that:

  • The more humid warmer weather viruses generally dislike is associated with a natural seasonal decline. 
  • More sunshine and consequent increasing levels of Vitamin D are important. Some think, with much evidence, this is the main factor, I covered this in a previous post and update and I will re-visit this again as the summer goes on and more evidence comes in.  
  • Social distancing and lockdown reduce transmissibility too, the earlier the better. 

At the same time, life is creeping back to the 'new normal' with increasing numbers back at work and more leisure. We are entering new territory, yet the decline in cases in the UK is painfully slow with implications for the future.  So what is going to happen now?

COVID and the summer.



The graph show the latest prediction of when the wave will finally end. I have been watching these particular number crunchers; the date they predict the end of the wave is moving further into the autumn as our cases decline far more less steeply than they increased at the start of the pandemic. 

The graph is already a little behind, but there are still 3000 test-positive cases daily in the UK. A prominent member of the iSAGE group, John Edmunds suggests the number is closer to 20,000 a day. The end is now predicted to be in September.


End of the first wave

COVID19 and next winter


If this is true, it means COVID19 will be around when:
  • The air becomes dryer and colder
  • Children head back to school
  • Students head off to university 
  • Vitamin D levels start to fall

So truly comprehensive systems to control local outbreaks will need to be ready. Early and perhaps more sensitive focused restrictions might be needed, perhaps on an local or regional basis. Testing and tracing will have to be rapid and efficient and we will have to plant some more money trees to fund it all.  Thats another story I will cover in another post.

Meanwhile in a distant pig factory in Utah, or a poultry factory in Guangdong, viruses are meeting and mutating into new and novel forms. Thats another story too.......