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Covid-19: Was the decision to delay the UK’s lockdown over fears of “behavioural fatigue” based on evidence?

BMJ 2020; 370 doi: (Published 07 August 2020) Cite this as: BMJ 2020;370:m3166

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  1. Elisabeth Mahase
  1. The BMJ

“We have to take the right steps at the right time.” That’s the message the UK government has repeated when asked why stricter measures to control the spread of covid-19 weren’t implemented in early March. This was often followed by what became the catchphrase of the pandemic response: “We’re following the science.”

As Italy announced a countrywide lockdown on 9 March, people wondered why the UK wasn’t following suit. At that time Italy had over 9000 cases of covid-19 and nearly 500 deaths, up from 153 cases and three deaths two weeks earlier. Many people were calling for prompt action in the UK, which had had four deaths up to 9 March. But the UK’s lockdown didn’t come until 23 March, a delay that many people claim has cost lives.

What did officials say about the timing?

Speaking at a live televised briefing on 9 March, England’s chief medical officer, Chris Whitty, said, “It is not just a matter of what you do but when you do it. Anything we do, we have got to be able to sustain. Once we have started these things we have to continue them through the peak, and there is a risk that, if we go too early, people will understandably get fatigued and it will be difficult to sustain this over time.”

On 12 March he added, “An important part of the science on this is actually the behavioural science, and what that shows is probably common sense to everybody in this audience, that people start off with the best of intentions, but enthusiasm at a certain point starts to flag.”

This idea of behavioural fatigue for measures such as lockdown was repeated in other briefings—including by the prime minister, Boris Johnson, and the UK’s chief scientific adviser, Patrick Vallance—and it has since seemingly been treated as fact.

The deputy chief medical officer, Jenny Harries, told the US news outlet NBC News on 11 March,1 “Just because a lockdown is imposed doesn’t mean that that is the right thing to do. Timing of an intervention is absolutely critical. Put it in too early, you have a time period [where] people actually get non-compliant—they won’t want to keep it going for a long time.”

What’s the evidence for behavioural fatigue?

It seems logical that the idea of behavioural fatigue would come from the Independent Scientific Pandemic Influenza Group on Behaviours (SPI-B), a subcommittee of the Scientific Advisory Group for Emergencies (SAGE),2 which has been advising the UK government. But the only apparent relevant section in the group’s minutes from 4 March states,3 “Empirical evidence for the behavioural and social impact of, and adherence to, each of the strategies is limited. We are not aware of any evidence on their interaction.”

Writing in The BMJ,4 Susan Michie, professor of health psychology, and Robert West, emeritus professor of health psychology—both members of SPI-B—said that the term “behavioural fatigue” was “an ill-defined new term that had no basis in behavioural science.”

They added, “Common sense understanding is not enough and can often lead to interventions that are at best wasteful and at worst counterproductive . . . For example, the common sense idea of ‘behavioural fatigue’ and concern that locking down too early may lead to widespread non-adherence later, was invoked in the UK for justification of the catastrophic delay of strict social distancing measures in the UK.”

The so called “Nudge Unit” may seem to be another possible source of the idea of behavioural fatigue. But this unit, which is actually called the Behavioural Insights Team (BIT), denies any link to the term.

“The notion, idea, of ‘behavioural fatigue’ absolutely, categorically, did not come from us or anyone at BIT,” its head of communications, Richard O’Brien, told The BMJ. “We did not propose fatigue as grounds to delay or shorten social distancing or any other measures aimed at covid-19. However the phrase entered the public or policy discourse, it was not from us.”

What does the government say?

Asked for the evidence behind Whitty’s statement on behavioural science at the 12 March briefing, the Department of Health and Social Care said that SAGE had agreed that a balance needed to be struck between interventions that theoretically have significant impacts and the interventions that the public can feasibly and safely adopt in sufficient numbers over long periods. The department added that this was about balancing risks and that, at the time of the briefing, decision makers had much less information than they do now. The department’s press officer pointed to the minutes of the 14 March meeting.

While The BMJ was unable to locate any minutes from 14 March, SAGE minutes from 13 March5 suggest that the government was explicitly advised not to delay any appropriate measures owing to concerns over “difficulty maintaining behaviours.”

The minutes state, “There is some evidence that people find quarantining harder to comply with the longer it goes on. The evidence is not strong but the effect is intuitive. There is no comparable evidence for social distancing measures, but experience suggests it is harder to comply with a challenging behaviour over a long period than over a short period.”

They continue, “Difficulty maintaining behaviours should not be treated as a reason for not communicating with the public about the efficacy of the behaviours and should not be taken as a reason to delay implementation where that is indicated epidemiologically. Where the UK does not adopt measures seen in other countries, government should clearly explain its reasoning.”

What’s the verdict?

It seems that the government did not follow the science or the scientists. On 16 March, 681 behavioural scientists signed an open letter to the government raising concerns over the evidence behind behavioural fatigue.6 The group said, “We are not convinced that enough is known about ‘behavioural fatigue’ or to what extent these insights apply to the current exceptional circumstances. Such evidence is necessary if we are to base a high-risk public health strategy on it.”

They added that focusing on this idea seemed to have led the government to “believe that halting the spread of the disease is impossible.” They wrote, “Radical behaviour change may be able to do much better than this, and would, if successful, save very large numbers of lives. Experience in China and South Korea is sufficiently encouraging to suggest that this possibility should at least be attempted.”

They then called on the government to “share an adequate evidence base in support of” behavioural fatigue or reconsider its decisions.

Meanwhile, Michie told The BMJ, “‘Behavioural fatigue’ is not a scientific term—it does not feature in any theory of behaviour, there is no measure of it, and it is not a recognised term in behavioural science. It appears that someone made it up as a shorthand and then used it to justify a policy, but it also seems that no one appears willing to say where it came from.”

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