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The Hallet Inquiry: The credible asymptomatic evidence from Germany that wasn’t so credible.
The Hallet Inquiry: The credible asymptomatic evidence from Germany that wasn’t so credible.
Musings from Boris Johnson's day 1 testimony
On day 1 of Boris Johnson’s testimony, Mr Keith KC stated there was credible evidence of asymptomatic transmission from Germany, which Mr Hancock referred to in his testimony.
This is Hancock’s testimony:
However, as we’ve previously pointed out, the evidence from Germany wasn’t that credible after all.
A highly cited article, first published in January 2020, reported the Investigation of a COVID-19 outbreak in Germany resulting from a single travel-associated asymptomatic contact.
The index case was a Shanghai resident who had visited Germany between January 19 and 22 for business reasons. The NEJM article reported she had been well with no signs or symptoms of infection but had become ill on her flight back to China, where she tested positive for 2019-nCoV on 26 January.
However, additional information from in-depth interviews published in May clarified that the index case did have symptoms compatible with COVID-19 at the time of her visit to Germany.
“Patient 0, who was an employee of the Chinese branch of a German company based in greater Munich, travelled from Shanghai to Munich by aeroplane on Jan 19, 2020, to facilitate workshops and attend meetings in the company building. The day after arrival (Jan 20, 2020), patient 0 felt chest and back aches—which she reported to be unusual—and took a single dose of medicine containing paracetamol. The patient reported fatigue during her whole stay in Germany and attributed the symptom to jetlag. After an overnight flight back to Shanghai on Jan 22, the patient felt feverish.”
The NEJM publication, despite being incorrect and having a misleading title, has not been corrected. Cited over two and half thousand times, it had huge implications on what happened next - particularly the calls for mass testing.
We first published on the issue of asymptomatic on the 6th of April: We found 21 studies reporting between 5% and 80% of SARS-CoV-2 positives may be asymptomatic and that some of these will become symptomatic (pre-symptomatics)
In late 2020, we further reviewed the spread from asymptomatics and pre-symptomatics. We reported three studies providing evidence of probable asymptomatic transmission and two for presymptomatic transmission—concluding that high-quality studies provide probable evidence of SARS-CoV-2 transmission from presymptomatic and asymptomatic individuals, with highly variable estimated transmission rates.
Problems in the Inquiry arise because of the certainty the KCs and some witnesses ascribe to specific issues such as asymptomatic transmission. For example, Hancock was told that asymptomatic transmission did not exist with the other six coronaviruses known to transmit to humans.
It’s unclear who made this statement to Hancock, but it is ill-informed.
A Pubmed search reveals several articles reporting asymptomatic transmission before the pandemic (for the search, click here).
Asymptomatic SARS Coronavirus Infection among Healthcare Workers, Singapore
Asymptomatic Severe Acute Respiratory Syndrome–associated Coronavirus Infection
A Review of Asymptomatic and Subclinical Middle East Respiratory Syndrome Coronavirus Infections.
Take, for example, this systematic review on Asymptomatic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection that concludes, “The proportion of asymptomatic MERS cases were detected with increasing frequency as the disease progressed over time. Those patients were less likely to have comorbid disease and may contribute to the transmission of the virus.”
The pandemic has highlighted the problem with statements of certainty that give rise to confusing and contradictory conclusions. Unfortunately, the KCs seem unable to test faulty assumptions or reflect on what the evidence base tells us.
As it turns out, no one asked the Shanghai resident whether she had symptoms at the time of her visit to Germany. Early reports were rushed to publication but were based on flawed premises, and initial advice often did not reflect the available evidence. As for the extent of asymptomatic transmission, it remains unclear.
Credibility requires convincing evidence to support claims. So, what are we to think of those who make statements that contradict the evidence?
The Hallet Inquiry: The credible asymptomatic evidence from Germany that wasn’t so credible.
It seems a pity that we are having to dissect the workings and science of the Inquiry rather than of the pandemic management. Perhaps this is because, all these months in, we have yet to hear from a front line clinician. I have lost count of the number of times I have offered my experience; I may be retired but medicine is like riding a bike - once learned you cannot forget.
The only justification for a lockdown in the first instance was inadvertently revealed by Michael Gove when he implied that the virus was man-made and originated from Wuhan. At that initial point the uncertainty of what it might do fuelled the panic. As to whether it should have happened earlier that would not have altered things as the virus had been on the loose in the West probably since the end of November. What did matter, death wise, was the failure to institute the correct management in severe cases.
Anecdote: I am pretty sure I had Covid in December 2019. The symptoms fitted exactly but of course there was no test then.
Just read, again, an article published by PANDA on the Diamond Princess. Why was nothing learnt from this?