4 April 2020 by Jennifer
Two worrying examples of recent misinformation on COVID-19 transmission, from top bods at Public Health England and the National Health Service.
Since late January / early February 2020, there’s been evidence that COVID-19 can be infectious before any symptoms develop.
Yet official information from the NHS & Public Health England has been saying the opposite.
What we do know about the virus is that you’re unlikely to be infectious when you don’t have symptoms.
Then on 20 March, a video clip appeared on the official @NHSEngland Twitter account, featuring Professor Keith Willett:
…at the same time as the virus is emitted from that cell, you start to cough. That’s the first time you really become infectious..
So for the five days before, you’re probably not infectious.
In fact, what we know (and already knew then) shows that a lot of transmission has been before the infectious person had symptoms.
I find it disturbing that this misinformation is being distributed through official channels. How come scientists all over the world are sharing evidence about infectiousness before symptoms, yet UK health top bods are telling us we needn’t worry about it?
And you really can’t blame “the public” for being confused about what they’re meant to do, if you give them this kind of bad advice.
I would like to see an enquiry tracking down where this misinformation originated, and why it was still being actively propagated as late as 20 March 2020.
Had Prof Willett & Dr Phin seen the evidence for asymptomatic transmission, and decided to ignore it? Had they not seen it, and if not, why not, when it’s part of their job to follow the science?
In the rest of this article, I’ll add specifics about the chronology of what was known when, plus some additional lethal advice from Dr Phin on 13 March, saying it’s fine to go to the pub and visit elderly relatives.
- 30 January 2020: asymptomatic transmission formally documented in Germany
- 12 March 2020: Professor Christakis discusses transmission evidence so far
- 13 March 2020: Dr Nick Phin on Newsnight
- 20 March 2020: Professor Keith Willett via @NHSEngland
- Written information
- P.S. A note on the illustration
(Bold type on this page is mine, for easy skim-reading.)
On 30 January, a letter from a group of German doctors appeared in the New England Journal of Medicine: “Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany“.
It explains how someone in Germany had caught the virus via a business colleague visiting from Shanghai in January, even though she herself didn’t develop any symptoms till after her visit, while she was on her flight home.
The doctors flag up:
The fact that asymptomatic persons are potential sources of 2019-nCoV infection may warrant a reassessment of transmission dynamics of the current outbreak.
(Note on timestamps: The page says “This letter was published on January 30, 2020, and updated on February 6, 2020, at NEJM.org”.
There’s also a later date stamp on the page, “March 5, 2020”. I’m not sure what that refers to – maybe the publication date of a print copy? But at any rate, this letter is cited in other things dated February and the first few days of March, so it was clearly known in the international science community by then.
It seems to me likely that some Chinese doctors may have already figured it out around the same time, or earlier, as they’d been dealing with the illness for longer; but I haven’t yet seen a record of that if so.)
On 12 March, Nicholas A Christakis, Sterling Professor of Social & Natural Science at Yale, @NAChristakis on Twitter, wrote a thread discussing the existing evidence for asymptomatic transmission, based on several research papers (publicly available by then, albeit not yet peer-reviewed).
People are asking whether patients with COVID19 who don’t have symptoms, e.g. cough or even just fever, can transmit the disease to others. The answer seems to be yes. Alas, this is not good news, but we can still take rational steps. Let’s talk about this. …
If people are asymptomatic but have credibly been exposed to COVID19, they should be in home quarantine for 14 days, to be safe. But for how long can someone be asymptomatic and still transmit? It appears that this is on the order of 2-4 days.
… A careful study of 468 infector-infected pairs found that 12% involved transmission *before* the infector was symptomatic. [Reference, PDF: The serial interval of COVID-19 from publicly reported confirmed cases, 19 February]
A fine analysis of cases from China (N=135) & Singapore (N=93) found incubation was ~7-9 days. And there was pre-symptomatic transmission, with infection occurring on average 2.9 days (China) & 2.6 days (Singapore) before symptom onset in the infector [Reference, PDF: Transmission interval estimates suggest pre-symptomatic spread of COVID-19, 3 March]
Another analysis looking at 28 pairs of individuals suggests that “a substantial proportion of secondary transmission may occur prior to illness onset.” [Reference: Serial interval of novel coronavirus (2019-nCoV) infections, 17 February]
A further wrinkle is that these numbers are averages. Even if the latent period were not shorter than the incubation period on average, it could still be so for some patients. Indeed, this may be one of the factors that can make some individuals super-spreaders. …
In sum, on average, COVID19 patients take about 7 days from exposure to SARS-CoV-2 to show symptoms (typical range 2-14 days), and a meaningful percentage of carriers can spread the disease for 2-4 days before they are symptomatic.
I hadn’t seen the German doctors’ letter when it first came out, but I did see Prof Christakis’ summary thread around the time he wrote it.
Imagine my surprise, then, when I heard the Newsnight clip, apparently taken from the BBC’s Newsnight programme on 13 March 2020.
The speaker is Dr Nick Phin, Deputy Director of the National Infection Service at Public Health England.
(Transcript by me. I’ve skipped a few ums and ers.)
Interviewer: Will you be visiting an elderly relative, this weekend, for example?
Nick Phin: As long as you yourself feel – have no symptoms, then it’s a reasonable and perfectly acceptable thing to do. The key thing is that if you – if you develop symptoms, such as a temperature or fever, and a persistent dry cough, then you should stay at home, and stay at home for at least seven days.
Interviewer: This weekend, will you go to the pub?
Nick Phin: People can go to the pub. As long as they have no symptoms, there is – there is absolutely no restriction on their movements or what they do.
Interviewer: And what about slightly bigger gatherings, like a wedding, for example, where everybody knows each other, everybody’s likely to kiss each other, because it’s a family thing. Do you think weddings are something that you shouldn’t go to?
Nick Phin: What we do know about the virus is that you’re unlikely to be infectious when you don’t have symptoms. Therefore the – the clear message, if you like, for weddings and gatherings like that is to urge people that if they’re concerned that they may have a cough, or a fever, to stay away, and then that way you can try and make sure it’s a happy event.
Interviewer: So what about foreign holidays, then. Should people not be booking those, in the summer?
Nick Phin: There’s no reason why people shouldn’t book their holidays; I myself am gonnae go on holiday. The chances of getting coronavirus abroad and in the UK will be broadly similar.
He could have said “it’s early days, this is our best guess for now”. It would’ve still been a wrong guess, but a less declarative phrasing could’ve encouraged people to be cautious till they had more info. “We do know“, he assures us.
On 20 March, @NHSEngland shared a video clip from Professor Keith Willett, with the NHS branding. The text in the tweet describes it:
Our Strategic Incident Director Professor Keith Willett explains how #coronavirus spreads and how to avoid passing it on.
Here’s a transcript of the middle bit of the clip:
The way a virus gets into your body and causes illness, is it comes in onto your moist surfaces – your nose, your mouth, your throat.
It attaches to those cells, gets into the cell, and basically takes over the production line of your cell, producing tens of thousands of viruses.
The cell then breaks down; your body reacts for the first time, by giving you a temperature and a fever, because you’re now fighting something; and at the same time as the virus is emitted from that cell, you start to cough. That’s the first time you really become infectious..
So for the five days before, you’re probably not infectious.
But it’s important, then, if someone has coronavirus, and they start coughing, that they catch it in a tissue and bin it.
Prof Willett has hedged his statement a little bit, by throwing in the words “really” and “probably“.
It’s true we don’t know for sure exactly what proportion of people who catch COVID-19 is infectious before symptoms. But it isn’t something that hardly ever happens; remember, researchers concluded “a substantial proportion” of transmission seemed to have been “prior to illness onset“.
And even if it were pretty rare, there is such a thing as “erring on the safe side“, which is usually a good idea when it’s life and death. In some contexts, rather than speaking in terms of what’s “probable“, it’s more useful to give people a heads-up about the asymmetrically dangerous possibilities. For example, we warn people that carbon monoxide poisoning can be fatal, even though some people only get a bad headache from it.
It would be irresponsible to reassure someone “If you play Russian Roulette, you probably won’t die” – even though you could argue from a literal reading of “probably” that it’s technically true, as it’s “only” a 1 in 6 chance.
(I do wonder if Prof W had seen some of the contrary evidence by then, and that’s why he threw in those words. Like, maybe there was a steer from the government saying “we want things to carry on as normal”, or maybe someone argued that “the public” was too stupid to understand the concept of asymptomatic transmission, or for some other reason the official line was “we’re convincing people this isn’t a risk” – yet, knowing it wasn’t really true, he couldn’t bring himself to 100% straightforwardly lie. Hence a form of words that’s technically arguable, while still undoubtedly misleading.)
This misinformation correlates with official written info in the week or so prior to the schools closing & suchlike. I saw several things advising people to stay home “if you have a cough or fever” – “if“, implying that if you don’t have a cough or a fever, you’re OK to carry on going around as normal.
At the time, I was worried about that form of words leaving people to draw the wrong conclusion. But at first I thought it was just poor communication skills failing to convey the risk – not that “ignore this risk” was actually the intended message at the time!
I wanted to add a note on my choice of illustration for this post.
In many contexts, I think you get furthest by trying to understand facts and statements and emotions and points of view, as distinct from focusing personally on the individual people involved. The overall framing I like for when humans get things wrong is a combination of “what’s the systemic issue which allowed this to happen” combined with “people make mistakes, the question is what you then do about it”.
So I feel a bit funny about using people’s individual photos alongside a big note of WRONG! I had to think it over: did I really want to? did I think that was fair & ethically right?
Eventually I came down on the side of including the screenshots. The main reason is that I still have a pretty giant concern about this dangerously misleading info going around, and I wanted to help people to recognise “oh that’s that video I saw!” and have the chance to reconsider what they’d been told.
It also influenced me that the statements were made as part of these two people’s professional roles, in which they have ethical responsibilities to do no harm.
It’s not coincidence, however, that I stuck the “WRONG” label on top of the words, rather than on top of the people’s pictures. Their advice was wrong; as humans, they still have the opportunity to actively contradict the misleading advice, and apologise for the deaths and pain that their words may already have led to.