Why experts disagree about covid-19

A leading University of East Anglia (UEA) academic has called for greater international collaboration to give the public more confidence in official advice about Covid-19.

Infectious disease expert Prof Paul Hunter, from UEA’s Norwich Medical School, argued that confusion stemming from conflicting advice between - and sometimes within - countries had set back the effectiveness of public health messages and interventions.

He was speaking on Thursday 25 June as part of UEA’s (now online) London Lectures series and, as part of a lively discussion, covered recent disputes including the effectiveness of face masks, school closures, and one or two metre social distancing.

Watch a recording of the full lecture here:

Prof Hunter said that in all three of these areas the public had understandably been confused by
contradictory messages and interpretations of the evidence “despite the fact that everybody has been ‘following the science’” - asking “why do experts disagree?” as the title for his talk.

He said: "While research has shown that most people can distinguish between fake news and reality ... the big problem was the confusion in the information that the government was trying to get across.”

He explained that a number of factors made this problem particularly acute when it came to Covid-19.

These included that: Covid-19 was a new pathogen with limited data available that was often then over-interpreted; incorrect assumptions had been made that it would follow a similar pattern either to Sars or influenza, which led to flawed hypotheses and modelling; and that the demand for advice had led to too many scientists acting outside their area of expertise.

For example, while closing schools could prove to be highly effective in tackling Covid-19, early assessments of this based on responses to Sars were likely to have been misleading due to differences in the points at which Sars and Covid can be transmitted.

Prof Hunter also argued that a more fundamental reason for scientific dispute comes from researchers misinterpreting what should be considered the hierarchy of evidence, with too much weight given to mathematical modelling and laboratory experiments compared to randomised control trials or real life scenarios.

For example, lab experiments on facemasks had shown their use in reducing transmission whereas a Polish study had shown that their effectiveness actually soon wears off as itchiness from them makes wearers touch their face more.

While worth listening to, expert opinion should also be considered the lowest form of credible evidence when compared to the “gold standard” of systematic reviews, he added. Whereas in debates on Covid-19, single expert opinions had too often been taken as of equal worth.

For example there is little hard data yet on how big a difference distancing of one or two metres will actually make, with too many multiple confusing factors at play such as mitigation through facemasks and the length of time people will spend that close to each other.

This problem of communications has also come at a time when Covid-19 has sparked huge public interest in the science on interventions, with UEA and partners’ papers on facemasks having “generated more feedback from members of the public than anything else I have written in my career".

In order to produce a clear set of agreed guidelines and avoid continuing problems into the future, Prof Hunter concluded that the lack of consensus makes it even more important that there are more rigorous evaluations and systematic reviews of evidence, as well as better cross-border collaboration that standardises and makes use of international data.

“We need to work better with other countries to understand what works and give more confidence in the advice… Britain is not exceptional in the way infectious diseases affect the UK,” he argued, so should not have an exceptional response. 

He also called for a wider range of voices and expertise to be brought into bodies such as the government’s scientific advisory group SAGE to avoid problems such as groupthink - a psychological phenomenon where people strive for consensus within a group, resulting in a dysfunctional decision-making outcome.

After one of the best attended lectures in the series so far, participants posted a wide range of questions on herd immunity, local R rates and whether there is a role for philosophers in broadening the range of debate.

Prof Hunter was also asked what the most confusing message from the government had been. He replied that ministers and officials had given the impression that it was: "Okay for political advisers to go on days out to Barnard Castle but not for the rest of us.

“That does seem to have changed attitudes to lockdown,” he said, adding that: “One of the most depressing things has been that the CMO (Chief Medical Officer) in Scotland, a senior adviser to the Prime Minister and a member of SAGE didn’t seem to think that the rules applied to them.”

Prof Hunter also predicted that it was “inevitable” that there will be a second spike of Covid-19 in the UK in the autumn which could further overwhelm the NHS.

“If at that time we decide we are not going to do any more social distancing measures then it will probably be worse than it was,” he said. “And even if the peak is not as big but coincides with other pressures, the pressures on the NHS will be worse.”

However, accepting that his initial predictions on the progress of Covid-19 at the start of the year had been wrong, he acknowledged that this expectation might be faulty too. And, as good scientists should be, he was open to new evidence and contradictory ideas.

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