Richard North, 09/05/2020  

Pretty much, every one of my conclusions about multiple or prolonged contact, set out in my post on 5 May and again in this post, is endorsed by a series of papers offered in this tweet posted by Dr Muge Cevik on 4 May.

If I'd had sight of these papers when I posted, I would have had the hard evidence to support that which made sense intuitively and led me to my conclusions. But while I only posted earlier this week, some of the papers date from mid-April. This rather suggests that those who are actually charged with the management of this epidemic – and are paid for so doing – have been asleep on the job.

My conclusions are supportable by an increasing volume of evidence over the period, the summation of which have considerable implications for the lockdown, and for which restrictions should be lifted.

If we take this paper, for instance (published as a pre-print which had not been peer-reviewed), we can look at the: "Household Secondary Attack Rate of COVID-19 and Associated Determinants".

Based on a comprehensive contact-tracing dataset from Guangzhou, a group of Chinese researchers found that the SARS-Cov-2 virus was more frequently transmitted between household contacts when they remained together than when they were isolated after the infection had been detected.

In this paper, from the Lancet on 27 April, we see again the results from symptomatic surveillance and contact tracing by Chinese researchers. Their work suggested that household contacts and those travelling with a case were at higher risk of infection.

However, an even earlier paper, published on 6 March by the US CDC, hints at the same phenomenon, with high transmission rates between members of the same households – but amongst "close contacts", such as spouses (confirmed by this paper). Travel seemed to be less important.

We the have another paper - with a publication date of 8 May, but obviously available earlier. This concluded that living with an infected person constituted the highest risk, followed by taking the same transportation and then sharing "dinner and entertainment", with the stress on "close contact".

On 11 April, however, there had been a paper on the cluster of Covid-19 at a chalet in the French Alps during February. With an attack rate of 75 percent, this also pointed to the effects of close contact.

A month earlier, we have another interesting paper which charts a woman who had travelled from China to Illinois, USA, subsequently to develop Covid-19 symptoms which necessitated her hospitalisation. Her husband, who had not travelled, but had had frequent close contact with his wife, was admitted to hospital eight days later and tested positive for SARS-Cov-2.

But the interesting thing here is that there had been 372 contacts of both cases. Of those, 347 underwent active symptom monitoring, including 152 community contacts and 195 health-care personnel. Of monitored contacts, 43 became persons under investigation. These, and all 32 asymptomatic health-care personnel, tested negative for SARS-Cov-2.

One point that immediately emerges from this was the flaw in the UK advice to people who believed they had been infected should stay at home, self-isolating with their families. The experience had already indicated that quarantining the first case, even after becoming symptomatic, reduced transmission to the rest of the family.

Yet another paper (published in the United States) looks at an outbreak in a nursing home, finding that twenty-three days after the first positive test result in a resident, 57 of 89 residents (64 percent) tested positive for SARS-Cov-2. Of the 57 residents, 11 were hospitalised (three in intensive care) and 15 died (mortality, 26 percent).

Putting these and other data into the mix, Cevik (rightly) asserts that close and prolonged contact is required for Covid-19 transmission, suggesting that the risk is highest in enclosed environments: household; long-term care facilities; and public transport.

From that, one can also conclude – as I have done – that casual, single contacts are unimportant. The emphasis should be on avoiding situations where people are exposed to continual or multiple infections over a period of time. I thus wrote recently:
… as well as healthcare and home nursing situations, we might think about checkout operators in supermarkets, bus drivers and any occupation with frequent customer interface – all of which might be regarded a "high risk". On the other hand, contacts in the street, parks and in other open spaces, may be irrelevant.
This clears the way to abandon much of the ritualistic social distancing. But another important point to emerge is the value of investigating cases and contact tracing, helping to build up a profile of the disease, providing evidence that can support policy-making and control decisions – in a way that the statistics alone cannot, and for which Mr Hancock's fatuous app and his gig-economy call centres are utterly valueless.

This is a drum I've been banging from the very beginning, arguing the case for "shoe-leather" epidemiology to help guide us through this crisis. Yet this is the area from which UK politicians and their "experts" have quite deliberately excluded themselves, preferring the number-crunching of Ferguson and his allies.

Now, even the Telegraph has belatedly woken up to the value of traditional epidemiology, although leavening its awakening with the pompous observation that "almost every day now, a new study is published that shines light on the way in which the new coronavirus is spread".

We are then told that the "latest findings" come not from epidemiological estimates but from analysis of dozens of actual Covid-19 clusters unpicked by contact and trace teams from around the world.

"These studies" we are thus informed, "are like a forensics report from a crime scene. While a good psychological profiler can point detectives in the right direction, the CSI team gives them the smoking gun".

This is from Paul Nuki, the Telegraph's "global health security editor" – there's glory for you. But his crass intervention, where he remarks that the findings don't come from "epidemiological estimates", tells us a great deal. The inference is that the Ferguson version of epidemiology is the real thing, illustrating how much the number-crunchers have polluted the discipline.

Yet, in his short career as "global health security editor", this is probably the first time that Nuki has met real epidemiology, naked in tooth and claw – the process of real time observation and deduction. This comes from people who have a feeling for the job and the way infectious disease works, something you will never get from sitting at a computer playing with models.

But then, all of a sudden, reality is breaking through. After presiding over a series of disasters tempered by ocean-going incompetence, the government is apparently to ask public health directors in England to take charge of Covid-19 testing in care homes – seen as an admission that centralised programmes have "fallen short".

This is, of course, what should have been done right at the very start of this epidemic – along with decentralised contact tracing. We thus have a government which seems to have reverted to a style of administration attributed (by Churchill, it is claimed) to the Americans, where they can always be counted on to do the right thing, after they have tried everything else.

On those same lines, we now have Sky News discovering that there are considerable local variations in the incidence of Covid-19, with clear differences within the UK's nations and regions.

Next thing you know, they might even work out that there isn't one outbreak, that the terms "outbreak" and "epidemic" are not synonymous, and that the way to tackle this epidemic is one outbreak at a time – just as the public health directors are about to do.

In the meantime, it is probably fair to say that thousands have died unnecessarily, while the government has taken time out to re-learn the basics of epidemiology, and gets up to speed on the fundamentals. But then, I suppose, it really has tried just about everything else. Now is the time to give competence a chance.

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