I discuss the UK government’s definition of the COVID-19 policy problem in some other posts (1. in a now-dated post on early developments, and 2. in relation to oral evidence to the Health and Social Care committee). It includes the following elements:
- We need to use a suppression strategy to reduce infection enough to avoid overwhelming health service capacity, and shield the people most vulnerable to major illness or death caused by COVID-19, to minimize deaths during at least one peak of infection.
- We need to maintain suppression for a period of time that is difficult to predict, subject to compliance levels that are difficult to predict and monitor.
- We need to avoid panicking the public in the lead up to suppression, avoid too-draconian enforcement, and maintain wide public trust in the government.
- We need to avoid (a) excessive and (b) insufficient suppression measures, either of which could contribute to a second wave of the epidemic of the same magnitude as the first.
- We need to transition safely from suppression measures to foster economic activity, find safe ways for people to return to work and education, and reinstate the full use of NHS capacity for non-COVID-19 illness.
- In the absence of a vaccine, this strategy will likely involve social distancing and (voluntary) track-and-trace measures to isolate people with COVID-19.
This understanding in the UK, informed strongly by SAGE, also informs the ways in which SAGE (a) deals with uncertainty, and (b) describes the likely impact of each stage of action.
Manage suppression during the first peak to avoid a second peak
Most importantly, it stresses continuously the need to avoid excessive suppressive measures on the first peak that would contribute to a second peak [my emphasis added]:
- ‘Any combination of [non-pharmaceutical] measures would slow but not halt an epidemic’, 25.2.20: 1).
- ‘Mitigations can be expected to change the shape of the epidemic curve or the timing of a first or second peak, but are not likely to reduce the overall number of total infections’. Therefore, identify whose priorities matter (such as NHS England) on the assumption that, ‘The optimal shape of the epidemic curve will differ according to sectoral or organisational priorities’ (27.2.20: 2).
- ‘A combination of these measures [school closures, household isolation, social distancing] is expected to have a greater impact: implementing a subset of measures would be ideal. Whilst this would have a more moderate impact it would be much less likely to result in a second wave. In comparison combining stringent social distancing measures, school closures and quarantining cases, as a long-term policy, may have a similar impact to that seen in Hong Kong or Singapore, but this could result in a large second epidemic wave once the measures were lifted’ (Meeting paper 4.3.20a: 3).
- ‘SAGE was unanimous that measures seeking to completely suppress spread of Covid-19 will cause a second peak. SAGE advises that it is a near certainty that countries such as China, where heavy suppression is underway, will experience a second peak once measures are relaxed’ (also: ‘It was noted that Singapore had had an effective “contain phase” but that now new cases had appeared) (13.3.20: 2)
- Its visual of each possible peak of infection emphasises the risk of a second peak (Meeting paper 4.3.20: 2).
- ‘The objective is to avoid critical cases exceeding NHS intensive care and other respiratory support bed capacity’ … SAGE ‘advice on interventions should be based on what the NHS needs’ (16.3.20: 1)
- The fewer cases that happen as a result of the policies enacted, the larger subsequent waves are expected to be when policies are lifted (SPI-M-O Meeting paper 25.3.20: 1)
- ‘There is a danger that lifting measures too early could cause a second wave of exponential epidemic growth – requiring measures to be re-imposed’ (2.4.20: 1)
Avoid the unintended consequences of epidemic suppression
This understanding intersects with (c) an emphasis of the loss of benefits caused by certain interventions (such as schools closures).
- SPI-B (Meeting paper 4.3.20b: 1-4) expresses reluctance to close schools, partly to avoid the unintended consequences, including: displacement problems (e.g. school closures prompt children to be looked after by vulnerable older people, or parents to lose the chance to work); and, the unequal impact on poorer and single parent families (loss of school meals, lost income, lower internet access, exacerbating isolation and mental ill health). It then states that: ‘The importance of schools during a crisis should not be overlooked. This includes: Acting as a source of emotional support for children; Providing education (e.g. on hand hygiene) which is conveyed back to families; Provision of social service (e.g. free school meals, monitoring wellbeing); Acting as a point of leadership and communication within communities’ (4.3.20b: 4).
- ‘Long periods of social isolation may have significant risks for vulnerable people … SAGE agreed that a balance needs to be struck between interventions that theoretically have significant impacts and interventions which the public can feasibly and safely adopt in sufficient numbers over long periods. Input from behavioural scientists is essential to policy development of cocooning measures, to increase public practicability and likelihood of compliance … the public will face considerable challenges in seeking to comply with these measures, (e.g. poorer households, those relying on grandparents for childcare)’ (10.3.20: 2).
- After the lockdown (23.3.20), SAGE describes a priority regarding: ‘how to minimise potential harms from the interventions, including those arising from postponement of normal services, mental ill health and reduced ability to exercise. It needs to consider in particular health impacts on poorer people’ (26.3.20: 1-2).
Exhort and encourage, rather than impose
It also intersects with (d) a primary focus on exhortation and encouragement rather than the imposition of behavioural change (Table 1), largely based on the belief that the UK government would be unwilling or unable to enforce behavioural change in ways associated with China. In that context, the government’s willingness and ability to enforce social distancing and business closure from the 23rd March is striking.
- when recommending ‘individual home isolation (symptomatic individuals to stay at home for 14 days) and whole family isolation (fellow household members of symptomatic individuals to stay at home for 14 days after last family member becomes unwell)’, it assumes a 50% compliance rate, and notes that ‘closing bars and restaurants ‘would have an effect, but would be very difficult to implement’ (5.3.20: 1).
See also: oral evidence to the Health and Social Care committee, which suggests that the UK government and SAGE’s problem definition contrasts with approaches in countries such as South Korea (described by Kim et al, and Kim).
It also contrasts with the approach described by several of the UK’s (expert) critics, including Professor Devi Sridhar (Professor of Global Public Health), who is critical of SAGE specifically, and more generally of the UK government’s rejection of an ‘elimination’ strategy:
Table 1 sets out one way to describe the distinction between these approaches:
- The UK government is addressing a chronic problem, being cautious about policy change without supportive evidence, identifying trigger points to new approaches (based on incidence), and assuming initially that the approach is based largely on exhortation.
- One alternative is to pursue elimination aggressively, adopting a precautionary principle before there is supportive evidence of a major problem and the effectiveness of solutions, backed by measures such as contact tracing and quarantine, and assuming that the imposition of behaviour should be a continuous expectation.
One approach highlights the lack of evidence to support major policy change, and therefore gives primacy to the status quo. The other is more preventive, giving primacy to the precautionary principle until there is more clarity or certainty on the available evidence.
In that context, note (in Table 2) how frequently the SAGE minutes state that there is limited evidence to support policy change, and that an epidemic is inevitable (in other words, elimination without a vaccine is near-impossible). Both statements tend to support a UK government policy that was, until mid-March, based on reluctance to enforce a profound lockdown to impose social distancing.
As the next post describes, the chronology of Table 2 is instructive, since it demonstrates a degree of path dependence based on initial uncertainty and hesitancy. This approach was understandable at first (particularly when connected to an argument about reducing the peak of infection then avoiding a second wave), before being so heavily criticised only two months later.