Health and Housing

A series of posts exploring the links between health and housing.

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Seeing your “R’s”

It seems to becoming clear that in order to transition out of lock down a strategy of testing, tracing, isolating and quarantining (TTIQ), at scale, needs to be adopted. What is interesting is how “the science”  around all this in the UK seems to evolve, almost in lock step, with the availability of the resources to implement the science. This helpfully means the Government can pretty much always do the right thing at the right time.

But how much testing needs to be done? To address this I guess one question is, what is testing for? From a lay persons point of view it seems to me there are broadly three purposes to testing.

First, a clinical one. This is about testing to identify which people, exhibiting serious symptoms are actually infected with Covid-19. The outcome of this being critical in determining the way the patient is managed.

Another clinical reason for testing is to check those managing the disease, working closely with patients and caring for the most vulnerable are not infected and thus in danger of spreading the disease. Ideally, I guess you would want to test front line staff perhaps once a week to ensure they are not working whilst infected but asymptomatic.

With these types of testing you would expect the ratio of positive to negative results as likely to be high. Essentially you are using self selected samples of most at risk people and therefore most likely to prove to have the disease. As of 9.00am on 30 April roughly 690k people had been tested and of those 170k tested positive which is almost 25% of those tested.

The second purpose for testing we might call epidemiological. It is about trying to understand the progress of the disease, its prevalence and spread, where the hot spots are etc. How effective this testing is will probably be critical to the design and success of any transition out of lock down.

This is what I take Pillar 4 of the testing regime to be partly about.  Currently the numbers devoted to this are very low, just short of 10k out of the 690k tested to date. It may be that fancy sampling techniques means this is sufficient. However none of these random tests have so far proved positive so to a lay person this suggests a larger sample may be needed.

Given the 25% ratio between sampling and disease in the self selected groups mentioned above and the zero infection rate in the Pillar 4 sample you suspect there must be a Goldilocks sample size and structure that gives more useful information. One suspects  the size of Pillar 4 sample is currently being determined by availability of tests rather than statistical design.

The third role for testing  is “R” management. This is about running a “wack a mole” programme of early identification of potential carriers and trying to break the chain of infection, of which they are a link, as soon as possible.

We know when we come out of lock down the disease will still be with us, lurking in the community. Success will be about managing not eliminating infection. Keeping the “R” as low as possible, so those who contract the disease and require critical care do not overwhelm the NHS. Or indeed take up all available resource thus increasing the collateral, non Covid-19, mortality rate.

In lock down “R” was controlled by the radical separation of people. Confining them within their homes. The less opportunity people have to interact at all the less opportunity for the disease to spread. This does appear to have been effective  but it is incredibly disruptive economically, socially and also, as time goes by, on people’s mental and physical health.

Having applied the hammer of lock down to get the “R” down to something below 1 we now need to look for more sophisticated ways of managing the spread to keep the “R” in check without lock down. Presumably when the R is above a certain level the only way to control it is through lock down. But when you get it below a certain level (something below 1) the progression of the disease is at least susceptible to less disruptive forms of management.

Social distancing protocols will be important in this but it is impossible they will be as effective as lock down so the virus will inevitably begin to spread again. This is where TTIQ at scale comes in, breaking the chain of infection as soon as the mole emerges into the light.

Ideally of course you would like to track it and intervene before it fully emerges into the light. To do this you would have to test everyone at least once a week to keep absolutely on top of the disease. That is 66m tests per week, 3.4bn tests a year. Mmm, probably not.

In the absence of this fanciful ideal what you need is a very agile and fast regime of TTIQ which responds immediately to individuals with even minimum symptoms, ideally supplemented with some large scale randomised tests to try and get ahead of the disease.

This means having significant numbers tests available and Test and Trace teams. Their job would be to go out as soon as someone identified as symptomatic, even if mild flu like symptoms, and test them. If the test was positive isolating those individuals and then tracing all of their contacts over, say, the past two weeks and ensuring those most at risk are tested and quarantined. For this, speed is obviously of the essence, as every day an infected person is not isolated they are spreading the disease.

TTIQ is foremost a logistical challenge. You need teams of well trained individuals with excellent interpersonal skill. Able to instantly respond to cases in the community, test the person, identify, trace, meet and test all their high risk contacts. Harvard Global Health Institute estimated an average of 10 tests of contacts per infected person.

Given all this how many Test and Trace teams would you need? That has to be a function of how many suspected cases are identified in the community per day. And how many cases a team can manage effectively per day. These are a couple of questions journalists might like to ask.

A related issue is the number of tests available to be used by the Test and Trace Teams. We should be up to 100,000 per day by now. Is that enough? In a recent blog, “Dancing out of lock down” I talked about research coming out of Harvard Global Health Institute suggesting a minimum number of tests as being of the order of 152 per 100k population. Which for the Uk seemed to work out at around 100k tests.

Whether this is right or not remains to be seen. An alternative estimate of the numbers needed comes from Tomas Pueyo who has now written a series of articles on the progress of Corvid-19 and how it is being managed. His latest is precisely about how to do testing. Initially I was cautious about Mr Pueyo’s credentials on this issue, however, over time I have found his common sense approach much more informative and convincing than the carefully honed statements of the UK press briefings.

Mr Pueyo argues sampling needs to be such as to ensure the proportion of positive outcomes is below 3%. This is what those countries which seem to have managed the disease well have done with early mass testing. Whilst I see the logic of his argument I guess this must be sensitive to the stage of the disease and thus general level of infection in the population. However, given all countries are probably at an early stage in this pandemic this is probably not a fatal criticism at the moment.

In the absence of statistically significant random testing identifying the level of “R” must involve working back from hospitalisation and death rates and some, no doubt, very clever epidemiological statistical manipulation.

The problem with this is you are looking backwards at the “R” rate which existed some days previously, and days matter. Fast and effective Test and Trace teams will not stop transmission of the disease but they may ensure, together with social isolation protocols, that its progress is reduced and the “R” kept within what the NHS can manage until we get a vaccine.

Throughout this blog so far I have talked about “the” “R” as if there is a single infection rate. This is not the case. Whilst the “R” in the general community seems to be managed by lock down it does not seem to be anywhere near as well managed in those communities that are locked in care and nursing homes and those locked up in prisons.

Urgent action needs to be taken to support these communities or what is a tragedy for those that live there, their carers and their families will become an ongoing source of infection in the wider community. We need to be able to see and address all the “R’s”

If increased resources are not supplied to these current hot spots, and a combination of social distancing and TTIQ do not slow the disease down enough, over time it will accelerate and we will have to resort, once again, to the blunderbuss which is lock down.

The World Health Organisations advice on managing this disease was “testing, testing, testing”.  As the resources become available “the science” will show this is right and we will begin to do the “right thing at the right time” and see our “R’s”. The sooner the better.

 

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Dancing Out of Lock Down – A Slowy

How do we get out of lockdown? Clearly the government are wrestling with the issue as we speak. They don’t want to share their thinking as they’re afraid the great British public are incapable of holding two ideas in their mind at the same time. Clearly, the government can draw on the advice of all manner of highly qualified professional advisors. And it is certain that whatever strategy eventually emerges will be guided by “the science”.

In what follows I attempt to think through some of the issues from a lay persons point of view. This is not to second guess what “the science” will show but to be able to ask sensible questions of the science when it emerges.

Some of the most consistently informative and convincing material I have read about Covid-19 has been that produced by Tomas Pueyo whose characterisation of the progression of the disease is particularly persuasive. He identifies basically two phases which he labels The Hammer and The Dance, illustrated below. In essence the Hammer is getting a grip of the disease and suppressing the spread.  This is done through strict social distancing and lockdown. The Dance is where the lower rate of infection is maintained by retaining social distancing after lockdown but supplementing this with testing, tracing and isolation.

This process is inevitable in the absence of either a vaccine, a cure or herd immunity. All the evidence seems to be that the first two are unlikley to be available for some 12 to 18 months. This leaves herd immunity. However there are a series of problems with this.

First, it is not clear that individuals develop natural immunity. Second, even if we assume natural immunity is secured by infection and recovery then in a UK population of 66m people we need 39m to have contracted and survived the disease to get to the 60% personal immunity level needed for herd immunity.

How close are we to this number? In the absence of mass testing we can only guess at the number already infected.  If we assume that the mortality rate is 1% of those infected as of when I started writing this (Saturday 18 April) the number of those that have died in the UK is reported as 15,464. This would suggest just over 1.5m people have the disease. [Warning this is uninformed common sense and may be something an epidemiologist would laugh at.] Logic says we therefore need another 27.5m to get infected and survive.

This brings us to the third problem, which is the cost in lives of securing herd immunity. In the absence of any treatment reducing the mortality rate, in order to get to herd immunity we might expect the ultimate death toll to be in excess of 390k people (1% of 39m). Without breaking the link between infection and mortality rate via a vaccine or cure these numbers look logical but unacceptable.

This would suggest a strategy is needed which buys us time. In other words reduces the number of deaths until a vaccine or cure is found. This can be done by: a) minimising the overall infection rate, the infamous “R” and; b) reducing the “R” even lower amongst the most vulnerable population. The initiatives to date by the government can be said to have been successful id a little late at dealing with a), however the picture on b) is rather mixed. The proposal that those who are particularly vulnerable should shelter at home makes sense to achieve b) however allowing the disease to get hold in care homes is the exact opposite.

So coming out of lock down what does the government need to do? It has set out a 5 point plan:

  1. Protect the NHS ability to provide sufficient critical care and specialist treatment across the UK;
  2. Need a sustained and consistent decline in the daily death rate;
  3. Reliable data that the infection rate or “R” is down to manageable levels across the board;
  4. Confident operational challenges, specifically testing and PPE are in hand;
  5. Confident no proposed change will risk a second peak in infection that overwhelms the NHS.

At the moment evidence seems to be building that the first three of Dominic Raab’s five tests for the movement out of lockdown will soon be met.

Test 1 is clearly a minimum requirement. Demand must be brought down to well within the capacity of the equipped and staffed ICU beds in the UK. Clearly the current level of demand is far too high. Demand needs to be reduced to a level which can accommodate spikes in demand, and the need to restart elective surgery and urgent cancer treatments. It also has to be at a level which does not put such an intolerable strain on front line staff.

However once you have got the disease down to a manageable level you need to turn to Mr Raab’s last two tests. These look sensible but rather problematic.

PPE remains a mess with the scale of the problem reducing the further away you get from the front line. It remains the case that for significant numbers of nurses, doctors and carers the lack of supply of PPE is an existential fear. Senior management, on the other hand, is confident there is sufficient PPE, although they are happy to change the guidelines on what PPE is appropriate mid-crisis, and not in a more stringent direction.

Which brings us to testing. Testing is the music needed for the Dance.

Matt Hancock has committed to achieving 100k tests per day by the end of April. At the moment the number of tests actually being done per day is around 20k. Matt Hancock says “Ahh yes, but there is capacity for 40k”. Unfortunately success is not measured by capacity but by results. I could have run a lot faster but I didn’t. Capacity is a necessary precondition of results but it is not sufficient. If we had infinite capacity to test everyone in Wick it would not be that much help. But put that aside.

Are 100k, actually completed, tests per day enough? It turns out they may be just about there if estimates of the level of testing needed to effectively monitor the disease post lockdown in the US, by the Harvard Global Health Institute, are correct. They suggest that a testing rate of a minimum of 152 tests per 100k population are needed to effectively monitor and manage the disease. Such a level should enable those showing any signs of disease, even mild flu like symptoms, to be tested in the community plus an average of 10 contacts.

Given a population of 66m divided by 100,000 gives you 660, multiplied by 152 = 100,320 tests per day required in the UK. Clearly there may be demographic or geographic or cultural drivers that move these numbers a bit but you would have thought they were in the right ballpark

So in order to go to the Dance without risking a second, unmanageable wave of infection, we need in place an infrastructure to enable a minimum of 100k tests per day to be carried out, all the contacts of those testing positive to be traced and all those infected isolated. A lot to put in place in less than three weeks.

Trying to draw some conclusions from all this.

First, what may delay coming out of lockdown is not the reduction in death rates etc it may be more about the materials and logistics for managing the virus after the end of lockdown.

Second, the end of lockdown is not the status quo ante. Far from. Our social, cultural and economic lives will continue to be severely constrained for some 12 to 24 months after the end of lockdown.

Third, this has specific economic consequences. Turning the economy off is a lot more straightforward than turning it back on. If the government does not continue to provide support to businesses in what might be a very long transition phase. more businesses could go bust coming out of lockdown than did going in.

Third, vulnerable groups are likely in for a particularly tough time. The reality may be they need to “shelter” until there is a vaccine. If this is the proposal from government it is not acceptable. They need to apply their minds to drive “the science” to come up with some way in which the vulnerable can get out of their homes, particularly those that live alone. Some creative thinking on this should be happening now and by pressure groups for the elderly and sick not just the scientists.

As Churchill might have put it coming out of lockdown is not the end, it’s not even the beginning of the end, it may however be the end of the beginning.

 

 

 

 

 

 

 

 

 

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Masking the Future

The issue of the beneficial effect of face masks is much in the news at the moment. Whenever you hear people clarifying the position on masks you come away slightly more confused than when you started. The “science” has moved from, they have no beneficial effects, to they don’t stop you catching Covid-19 but they may reduce substantially the chance of you spreading it if you have caught it.

But even the latter “science” is followed by advice that the general public should still not use masks. Why? Accepting that the mask does not stop you getting the disease, surely if it reduces substantially your chance of spreading Covid-19 it is worth people wearing masks. I thought the whole point was to break the chain of infection and surely it does not matter whether it is the getting or the giving which breaks the chain.

Usually, when the discussion has got to this point the government spokesperson talks about the mask becoming a source of infection if you do not take it off properly or dispose of it properly. However, I guess if the mask is infected that is because it has stopped something that would otherwise be infecting your face.

The next argument is masks promote a misplaced feeling of security and undermines the commitment to social distancing and hand washing. I suspect the contrary is true and that the face mask is a constant reminder of the risk of infection. However, that is just a hunch based on observing those with masks who seem, at least to me, to be more conscious of strict social distancing than those without. Of course that is just anecdotal, but I suspect it is the same evidence base as the “undermining commitment” theory.

Finally, they point to the advice of the World Health Organisation. That is definitely worth a look. There is a very interesting vides explaining “When to use a mask.” The video like much of the communication on Covid-19 requires close attention. 

It starts with a very clear statement that masks cannot protect against Covid-19 but then qualifies this with “when used alone”. It goes on to say you need to combine with hand washing and social distancing. Which sort of suggests it does have some benefit. This seems to be clarified when it goes on to say that WHO only recommend you wear a mask if you have symptoms of Covid-19. This would seem to support the prevention of spreading theory. The “giving” bit of the chain.

But then it goes on and says “There is no evidence that they (masks) protect people who are not sick” A very clear statement on the lack of prophylactic benefit. But the very next sentence says “However, if you are healthy but you are taking care of a person who [may be infected] then you should wear a mask whenever you are in the same room as that person.”

So wearing masks does not prevent you from getting the disease from an infected person however if you are with such a person you should wear a mask. All clear?

I suppose you might say this is an example of the “precautionary principle”, i.e. we have no evidence that it works but we have no evidence that it does not work either so what’s the harm in wearing it. Or that the virus is more/less virulent inside than outside and therefore the advice differs by location.

What comes across from this advice and much of the information that comes out of the UK press briefings is the need to listen very carefully to every word. The statements made are very carefully crafted to enable alternative interpretations to be put on them. 

I have no idea why the Government has taken such a clear position on face masks for the general public. My suspicion is that in a situation where front line health and care staff cannot get the PPE they need the Government don’t want any calls on supply or production that might divert the short supply that exists from them.

That is a perfectly reasonable position that I am confident the vast majority of the public would respect. I am pretty confident once supply issues are no longer a constraint the “science” on masks will change. We may then get advice on the matter which does not sound like a G7 communique that has been all night in the negotiation and which says – black is white except in circumstances where it is white.Masking the future

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Sorry seems to be the hardest word.

Priti Patel nearly got there. She nearly said sorry to the front line health workers and others who no Minister or advisor speaks of without praising for their bravery, commitment, professionalism etc. It is a compulsory part of the press briefing litany. Whilst it is wholly justified it is devalued when it appears to be used to deflect concern away from the deficiencies in the government’s management of issues such as PPE and testing.

Sadly Ms Patel did not apologise for the failings of government, she was sorry if, “…people feel there have been failings.” This goes to the heart of the weakness of the press briefings, a weakness which may undermine what is good about them.

The strengths of the briefings lie in detailed and, within understandable limitations, accurate information about the progression of the disease. They provide some objective scientific commentary on the likely trajectory of the disease. Finally, they communicate a consistent public information message about the vital importance of social distancing and the collective responsibility of all of us to limit the spread of the disease and cosequent impact on the NHS.

Where they are woefully inadequate is in holding the government to account on key government logistical responses to the disease. Questions by journalists which raise issues they have in hand get a solid response. The success of the construction of additional capacity in the  Nightingale Hospitals gets plenty of detailed response.

Questions about PPE on the other hand get batted away with a restatement of how critically important they are, how hard the government is working, (always night and day), and how many billions of pieces of PPE have been delivered in the past 24 hours.

Of course front line staff don’t need to be told how important it is. Indeed I suspect there is not a person in the country who does not now appreciate, if they did not before, the importance of infection preventing clothing for staff dealing with infected people.

How hard Ministers and others are working may be laudable but it is not what the question is about. And however large the number is of pieces of equipment delivered it is of little interest to the members of staff to whom it has not been.

At the start of this process when there was the debate about lock down people were suggesting that such an action in this country would not be as effective as in China where a) they are more used to obeying official edicts and b) those failing to obey would be dealt with harshly. In the event, once the lock-down was instituted the vast majority of people obeyed and have stuck to it pretty rigorously for the last three weeks. This is a testament to the widespread common sense of people across the country.

The government would do well to respect that common sense. It is blatantly clear that the country was ill prepared for a pandemic that was certain to arrive at some point. To be fair it shared that unpreparedness with pretty much every country in the world. The UK’s history as a trading nation and leadership role in the development of globalised supply chains created specific weaknesses. However, again it was not unique in this. When there is a global pandemic it is inevitable key materials will be in short supply and difficult to get hold of. 

If the government levelled on these issues and accepted PPE was not available in the quantities and the locations it was needed  but they were doing everything they could to address the issue people would have more time for them. Changing the guidelines on the types of PPE that can be worn in different circumstances during a shortage sounds like, what it probably is, an attempt to get the guidelines to fit the supply.

Suggesting those on the front line may be contributing to shortages by underusing equipment or using higher grade equipment than is strictly necessary is not helpful. It smacks of blaming the victims.

I, and I suspect most people, have a fund of good will towards the Government. They are dealing with something which none of us have experienced before, which moves at an unforgiving pace. A pace which magnifies any failures or delays in action with awful consequences. That good will fund however can be built upon by honesty and transparency or it can be squandered by obfuscation and transparent attempts to avoid responsibility.

We are where we are. It is clear there are shortages of PPE at the hospital ICU front line and clearly much worse problems in the social care sector. There is no point pretending otherwise. After Coronus we will need an Inquiry into what has gone wrong. I am sure the Government will come in for a share of criticism. However, there are failures in the response which transcend individual governments. National and global preparedness was clearly inadequate. Now is not the time to engage in a an inquisition.

The government should recognise the true state of affairs. They should apologise, not for peoples perceptions of failure but for their failure. They may be surprised how far a genuine apology goes.