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The overall narrative underpinning SAGE advice and UK government policy

SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions

COVID-19 policy in the UK: Table 2: Summary of SAGE minutes, January-June 2020

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July 8, 2020 · 8:35 am

COVID-19 policy in the UK: SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions

This post is part 6 of COVID-19 policy in the UK: Did the UK Government ‘follow the science’? Reflections on SAGE meetings

Limited testing

Oral evidence to the Health and Social Care committee highlights the now-well-documented limits to UK testing capacity and PPE stocks (see also NERVTAG on PPE). SAGE does not discuss testing capacity much in the beginning, although on 10.3.20 it lists as an action point: ‘Plans for how PHE can move from 1,000 serology tests to 10,000 tests per week’ and by 16.3.20 it describes the urgent need to scale up testing – perhaps with commercial involvement and to test at home (if can ensure accuracy) – and to secure sufficient data to track the epidemic well enough to inform operational decisions. From April, it highlights the need for a ‘national testing strategy’ to cover NHS patients, staff, an epidemiological survey, and the community (2.4.20), and the need for far more testing is a feature of almost every meeting from then.

Limited contact tracing

Initially, SAGE describes a quite-low contact tracing capacity: ‘Currently, PHE can cope with five new cases a week (requiring isolation of 800 contacts). Modelling suggests this capacity could be increased to 50 new cases a week (8,000 contact isolations)’ (18.2.20: 1).

Previously, it had noted that the point would come when transmission was too high to make contact tracing worthwhile, particularly since many (e.g. asymptomatic) cases may already have been missed (20.2.20: 2) and the necessary testing capacity was not in place (16.4.20): ‘PHE to work with SPI-M to develop criteria for when contact tracing is no longer worthwhile. This should include consideration of any limiting factors on testing and alternative methods of identifying epidemic evolution and characteristics’ (11.2.20: 3; see also Testing and contact tracing).

It returned to the feasibility question after the lockdown, with:

SPI-M (meeting paper 4.20d: 1-3) estimating that effective contact tracing (80% of non-household cases, in 2 days) could reduce the R by 30-60% if you could quarantine many people, multiple times; and,
SPI-B (meeting paper 4.20a: 1-3) advising on the need to clarify to people how it would work and what they should do, redesign physical spaces, and conduct new qualitative research and stakeholder engagement to ‘help us to understand more clearly the specific drivers, enablers and barriers for new behavioural recommendations’ to address an unprecedented problem in the UK (22.4.20a: 2). SPI-B also describes the trade-offs between app-informed systems (notification based on symptoms would suit people seeking to be precautionary, but could reduce compliance among people who believe the risk to be low) (see meeting papers 29.4.20: 3 and 5.5.20: 1-8)
SAGE noting ongoing work on clusters and super-spreading events, which necessitate cluster-based contact tracing (11.6.20: 3)
A more general message that contact tracing will be overwhelmed if lockdown measures are released too soon, raising R well above 1 and causing incidence to rise too quickly (e.g. 14.5.20)

Low capacity to achieve high levels of information necessary for forecasting

This type of discussion exemplifies a general and continuous focus on the lack of data to inform advice:

‘24. Real-time forecasting models rely on deriving information on the epidemic from surveillance. If transmission is established in the UK there will necessarily be a delay before sufficiently accurate forecasts in the UK are available. 25. Decisions being made on whether to modify or lift non-pharmaceutical interventions require accurate understanding of the state of the epidemic. Large-scale serological data would be ideal, especially combined with direct monitoring of contact behaviour. 26. Preliminary forecasts and accurate estimates of epidemiological parameters will likely be available in the order of weeks and not days following widespread outbreaks in the UK (or a similar country). While some estimates may be available before this time their accuracy will be much more limited. 27. The UK hospitalisation rate and CFR will be very important for operational planning and will be estimated over a similar timeframe. They may take longer depending on the availability of data’ (Meeting paper 2.3.20: 3-4).

A limited capacity to reach a relatively cautious consensus?

These limitations to information contributed to the difference between SAGE’s estimate on UK transmission (such as in comparison with Italy) and the UK’s much faster rate of transmission:

‘the UK likely has thousands of cases – as many as 5,000 to 10,000 – which are geographically spread nationally … The UK is considered to be 4-5 weeks behind Italy but on a similar curve (6-8 weeks behind if interventions are applied)’ (10.3.20: 1)

‘Based on limited available evidence, SAGE considers that the UK is 2 to 4 weeks behind Italy in terms of the epidemic curve’ (18.3.20: 1)

Rather, the UK was under 2 weeks behind Italy on the 10^th March, suggesting that its lockdown measures were put in place too late.

At the heart of this estimate was the under-estimated doubling time of infection (‘the time it takes for the number of cases to double in size’, Meeting paper 3.2.20a):

although described as 3-4 days (28.1.20: 1) then 4-6 days (Meeting paper 2.3.20) based on Wuhan, and 3-5 days based on Hubei (Meeting paper 3.2.20a),
SAGE estimates ‘every 5-6 days’ (16.3.20: 1) and states that ‘Assuming a doubling time of around 5-7 days continues to be reasonable’ (18.3.20: 1).
Only by meeting 18 does SAGE estimate the doubling time (ICU patients) at 3-4 days (23.3.20). By meeting 19, it describes the doubling time in hospitals as 3.3 days (26.3.20: 1).

Kit Yates suggests that (a) the UK exhibited a 3-day doubling time during this period (Huffington Post), and (b) although many members of SAGE and SPI-M would have preferred to model on the assumption of 3-days:

Having spoken to some of the modellers on SPI-M, not all of them were missing this. Many of the groups had fitted models to data and come up with shorter and more realistic doubling times, maybe around the 3-day mark, but their estimates never found consensus within the group, so some members of SPI-M have communicated their concerns to me that some of the modelling groups had more influence over the consensus decision than others, which meant that some opinions or estimates which might have been valid, didn’t get heard, and consequently weren’t passed on up the line to SAGE, and then further towards the government, so an over-reliance on certain models or modelling groups might have been costly in this situation (interview, Kit Yates, More or Less, 10.6.20: 4m47s-5m27s)

Yates then suggests that the most listened-to model – led by Neil Ferguson, published 16.3.20 – estimates a doubling time of 5-days, based on early data from Wuhan, using estimate of R2.4 (and generation time of 6.5 days), ‘which we now know to be way too low’ when we look at the UK data:

‘If they had just plotted the early trajectory of the epidemics against the current UK data at that point, they would have seen [by 14.3.20] that their model was starting to underestimate the number of cases and then the number of deaths which were occurring in the UK’ (interview, Kit Yates, More or Less, 10.6.20: 7m2s-7m15s)

Yates’ account highlights not only

the effect of uncertainty and limited capacity to generate more information, but also
the wider effect of path dependence, in which the (a) written and unwritten rules and norms of organisations, and (b) enduring ways of thinking (in individuals and groups, and political systems) place limits on new action. These limits are often necessary and beneficial, and often unnecessary and harmful.

Compare with Vallance’s oral evidence to the Health and Social Care committee (17.3.20: q96):

‘If you thought SAGE and the way SAGE works was a cosy consensus of agreeing scientists, you would be very mistaken. It is a lively, robust discussion, with multiple inputs. We do not try to get everybody saying exactly the same thing’.

The full list of SAGE posts:

COVID-19 policy in the UK: yes, the UK Government did ‘follow the science’

Did the UK Government ‘follow the science’? Reflections on SAGE meetings

The overall narrative underpinning SAGE advice and UK government policy

SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions

COVID-19 policy in the UK: Table 2: Summary of SAGE minutes, January-June 2020

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Tagged as COVID-19, sage, science advice, science advice to government, science and policy, science and policy making, Scientific advice to government, Scientific Advisory Group for Emergencies, UK Government, UK politics and policy

July 8, 2020 · 8:33 am

COVID-19 policy in the UK: SAGE Theme 1. The language of intervention

This post is part 5 of COVID-19 policy in the UK: Did the UK Government ‘follow the science’? Reflections on SAGE meetings

There is often a clear distinction between a strategy designed to (a) eliminate a virus/ the spread of disease quickly, and (b) manage the spread of infection over the long term (see The overall narrative).

However, generally, the language of virus management is confusing. We need to be careful with interpreting the language used in these minutes, and other sources such as oral evidence to House of Commons committees, particularly when comparing the language at the beginning (when people were also unsure what to call SARS-CoV-2 and COVID-19) to present day debates.

For example, in January, it is tempting to contrast ‘slow down the spread of the outbreak domestically’ (28.1.20: 2) with a strategy towards ‘extinction’, but the proposed actions may be the same even if the expectations of impact are different. Some people interpret these differences as indicative of a profoundly different approach (delay versus eradicate); some describe the semantic differences as semantics.

By February, SAGE’s expectation is of an inevitable epidemic and inability to contain COVID-19, prompting it to describe the inevitable series of stages:

‘Priorities will shift during a potential outbreak from containment and isolation on to delay and, finally, to case management … When there is sustained transmission in the UK, contact tracing will no longer be useful’ (18.2.20: 1; its discussion on 20.2.20: 2 also concludes that ‘individual cases could already have been missed – including individuals advised that they are not infectious’).

Mitigation versus suppression

On the face of it, it looks like there is a major difference in the ways on which (a) the Imperial College COVID-19 Response Team and (b) SAGE describe possible policy responses. The Imperial paper makes a distinction between mitigation and suppression:

Its ‘mitigation strategy scenarios’ highlight the relative effects of partly-voluntary measures on mortality and demand for ‘critical care beds’ in hospitals: (voluntary) ‘case isolation in the home’ (people with symptoms stay at home for 7 days), ‘voluntary home quarantine’ (all members of the household stay at home for 14 days if one member has symptoms), (government enforced) ‘social distancing of those over 70’ or ‘social distancing of entire population’ (while still going to work, school or University), and closure of most schools and universities. It omits ‘stopping mass gatherings’ because ‘the contact-time at such events is relatively small compared to the time spent at home, in schools or workplaces and in other community locations such as bars and restaurants’ (2020a: 8). Assuming 70-75% compliance, it describes the combination of ‘case isolation, home quarantine and social distancing of those aged over 70’ as the most impactful, but predicts that ‘mitigation is unlikely to be a viable option without overwhelming healthcare systems’ (2020a: 8-10). These measures would only ‘reduce peak critical care demand by two-thirds and halve the number of deaths’ (to approximately 250,000).
Its ‘suppression strategy scenarios’ describe what it would take to reduce the rate of infection (R) from the estimated 2.0-2.6 to 1 or below (in other words, the game-changing point at which one person would infect no more than one other person) and reduce ‘critical care requirements’ to manageable levels. It predicts that a combination of four options – ‘case isolation’, ‘social distancing of the entire population’ (the measure with the largest impact), ‘household quarantine’ and ‘school and university closure’ – would reduce critical care demand from its peak ‘approximately 3 weeks after the interventions are introduced’, and contribute to a range of 5,600-48,000 deaths over two years (depending on the current R and the ‘trigger’ for action in relation to the number of occupied critical care beds) (2020a: 13-14).

In comparison, the SAGE meeting paper (26.2.20b: 1-3), produced 2-3 weeks earlier, pretty much assumes away the possible distinction between mitigation versus suppression measures (which Vallance has described as semantic rather than substantive – scroll down to The distinction between mitigation and suppression measures). In other words, it assumes ‘high levels of compliance over long periods of time’ (26.2.20b: 1). As such, we can interpret SAGE’s discussion as (a) requiring high levels of compliance for these measures to work (the equivalent of Imperial’s description of suppression), while (b) not describing how to use (more or less voluntary versus impositional) government policy to secure compliance. In comparison, Imperial equates suppression with the relatively-short-term measures associated with China and South Korea (while noting uncertainty about how to maintain such measures until a vaccine is produced).

It is taking forever, but I think I am now managing to get into the rhythm of the February SAGE minutes (in relation to media interviews and oral evidence in March), at least enough to identify the need to interpret the text in a relatively thoughtful/ sympathetic way ….

— Professor Paul Cairney (@CairneyPaul) June 29, 2020

One reason for SAGE to assume compliance in its scenario building is to focus on the contribution of each measure, generally taking place over 13 weeks, to delaying the peak of infection (while stating that ‘It will likely not be feasible to provide estimates of the effectiveness of individual control measures, just the overall effectiveness of them all’, 26.2.20b: 1), while taking into account their behavioural implications (26.2.20b: 2-3).

School closures could contribute to a 3-week delay, especially if combined with FE/ HE closures (but with an unequal impact on ‘Those in lower socio-economic groups … more reliant on free school meals or unable to rearrange work to provide childcare’).
Home isolation (65% of symptomatic cases stay at home for 7 days) could contribute to a 2-3 week delay (and is the ‘Easiest measure to explain and justify to the public’).
‘Voluntary household quarantine’ (all member of the household isolate for 14 days) would have a similar effect – assuming 50% compliance – but with far more implications for behavioural public policy:

‘Resistance & non-compliance will be greater if impacts of this policy are inequitable. For those on low incomes, loss of income means inability to pay for food, heating, lighting, internet. This can be addressed by guaranteeing supplies during quarantine periods.

Variable compliance, due to variable capacity to comply, may lead to dissatisfaction.

Ensuring supplies flow to households is essential. A desire to help among the wider community (e.g. taking on chores, delivering supplies) could be encouraged and scaffolded to support quarantined households.

There is a risk of stigma, so ‘voluntary quarantine’ should be portrayed as an act of altruistic civic duty’.

‘Social distancing’ (‘enacted early’), in which people restrict themselves to essential activity (work and school) could produce a 3-5 week delay (and likely to be supported in relation to mass leisure events, albeit less so when work activities involve a lot of contact.

[Note that it is not until May that it addresses this issue of feasibility directly (and, even then, it does not distinguish between technical and political feasibility: ‘It was noted that a useful addition to control measures SAGE considers (in addition to scientific uncertainty) would be the feasibility of monitoring/ enforcement’ (7.5.20: 3)]

As theme 2 suggests, there is a growing recognition that these measures should have been introduced by early March (such as via the Coronavirus Act 2020 not passed until 25.3.20), and likely would if the UK government and SAGE had more information (or interpreted its information in a different way). However, by mid-March, SAGE expresses a mixture of (a) growing urgency, but also (b) the need to stick to the plan, to reduce the peak and avoid a second peak of infection). On 13^th March, it states:

‘There are no strong scientific grounds to hasten or delay implementation of either household isolation or social distancing of the elderly or the vulnerable in order to manage the epidemiological curve compared to previous advice. However, there will be some minor gains from going early and potentially useful reinforcement of the importance of taking personal action if symptomatic. Household isolation is modelled to have the biggest effect of the three interventions currently planned, but with some risks. SAGE therefore thinks there is scientific evidence to support household isolation being implemented as soon as practically possible’ (13.3.20: 1)

‘SAGE further agreed that one purpose of behavioural and social interventions is to enable the NHS to meet demand and therefore reduce indirect mortality and morbidity. There is a risk that current proposed measures (individual and household isolation and social distancing) will not reduce demand enough: they may need to be coupled with more intensive actions to enable the NHS to cope, whether regionally or nationally’ (13.3.20: 2)

On 16^th March, it states:

‘On the basis of accumulating data, including on NHS critical care capacity, the advice from SAGE has changed regarding the speed of implementation of additional interventions. SAGE advises that there is clear evidence to support additional social distancing measures be introduced as soon as possible’ (16.3.20: 1)

Overall, we can conclude two things about the language of intervention:

There is now a clear difference between the ways in which SAGE and its critics describe policy: to manage an inevitably long-term epidemic, versus to try to eliminate it within national borders.
There is a less clear difference between terms such as suppress and mitigate, largely because SAGE focused primarily on a comparison of different measures (and their combination) rather than the question of compliance.

See also: There is no ‘herd immunity strategy’, which argues that this focus on each intervention was lost in radio and TV interviews with Vallance.

The full list of SAGE posts:

COVID-19 policy in the UK: yes, the UK Government did ‘follow the science’

Did the UK Government ‘follow the science’? Reflections on SAGE meetings

The overall narrative underpinning SAGE advice and UK government policy

SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions

COVID-19 policy in the UK: Table 2: Summary of SAGE minutes, January-June 2020

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Filed under COVID-19, Evidence Based Policymaking (EBPM), Prevention policy, Public health, public policy, UK politics and policy

July 8, 2020 · 8:29 am

COVID-19 policy in the UK: SAGE meetings from January-June 2020

This post is part 4 of COVID-19 policy in the UK: Did the UK Government ‘follow the science’? Reflections on SAGE meetings

SAGE began a series of extraordinary meetings from 22nd January 2020. The first was described as ‘precautionary’ (22.1.20: 1) and includes updates from NERVTAG which met from 13^th January. Its minutes state that ‘SAGE is unable to say at this stage whether it might be required to reconvene’ (22.1.20: 2). The second meeting notes that SAGE will meet regularly (e.g. 2-3 times per week in February) and coordinate all relevant science advice to inform domestic policy, including from NERVTAG and SPI-M (Scientific Pandemic Influenza Group on Modelling) which became a ‘formal sub-group of SAGE for the duration of this outbreak’ (SPI-M-O) (28.1.20: 1). It also convened an additional Scientific Pandemic Influenza subgroup (SPI-B) in February. I summarise these developments by month, but you can see that, by March, it is worth summarising each meeting. The main theme is uncertainty.

January 2020

The first meeting highlights immense uncertainty. Its description of WN-CoV (Wuhan Coronavirus), and statements such as ‘There is evidence of person-to-person transmission. It is unknown whether transmission is sustainable’, sum up the profound lack of information on what is to come (22.1.20: 1-2). It notes high uncertainty on how to identify cases, rates of infection, infectiousness in the absence of symptoms, and which previous experience (such as MERS) offers the most useful guidance. Only 6 days later, it estimates an R between 2-3, doubling rate of 3-4 days, incubation period of around 5 days, 14-day window of infectivity, varied symptoms such as coughing and fever, and a respiratory transmission route (different from SARS and MERS) (28.1.20: 1). These estimates are fairly constant from then, albeit qualified with reference to uncertainty (e.g. about asymptomatic transmission), some key outliers (e.g. the duration of illness in one case was 41 days – 4.2.20: 1), and some new estimates (e.g. of a 6-day ‘serial interval’, or ‘time between successive cases in a chain of transmission’, 11.2.20: 1). By now, it is preparing a response: modelling a ‘reasonable worst case scenario’ (RWC) based on the assumption of an R of 2.5 and no known treatment or vaccine, considering how to slow the spread, and considering how behavioural insights can be used to encourage self-isolation.

February 2020

SAGE began to focus on what measures might delay or reduce the impact of the epidemic. It described travel restrictions from China as low value, since a 95% reduction would have to be draconian to achieve and only secure a one month delay, which might be better achieved with other measures (3.2.20: 1-2). It, and supporting papers, suggested that the evidence was so limited that they could draw ‘no meaningful conclusions … as to whether it is possible to achieve a delay of a month’ by using one or a combination of these measures: international travel restrictions, domestic travel restrictions, quarantine people coming from infected areas, close schools, close FE/ HE, cancel large public events, contact tracing, voluntary home isolation, facemasks, hand washing. Further, some could undermine each other (e.g. school closures impact on older people or people in self-isolation) and have major societal or opportunity costs (SPI-M-O, 3.2.20b: 1-4). For example, the ‘SPI-M-O: Consensus view on public gatherings’ (11.2.20: 1) notes the aim to reduce duration and closeness of (particularly indoor) contact. Large outdoor gatherings are not worse than small, and stopping large events could prompt people to go to pubs (worse).

Throughout February, the minutes emphasize high uncertainty:

if there will be an epidemic outside of China (4.2.20: 2)
if it spreads through ‘air conditioning systems’ (4.2.20: 3)
the spread from, and impact on, children and therefore the impact of closing schools (4.2.20: 3; discussed in a separate paper by SPI-M-O, 10.2.20c: 1-2)
‘SAGE heard that NERVTAG advises that there is limited to no evidence of the benefits of the general public wearing facemasks as a preventative measure’ (while ‘symptomatic people should be encouraged to wear a surgical face mask, providing that it can be tolerated’ (4.2.20: 3)

At the same time, its meeting papers emphasized a delay in accurate figures during an initial outbreak: ‘Preliminary forecasts and accurate estimates of epidemiological parameters will likely be available in the order of weeks and not days following widespread outbreaks in the UK’ (SPI-M-O, 3.2.20a: 3).

This problem proved to be crucial to the timing of government intervention. A key learning point will be the disconnect between the following statement and the subsequent realisation (3-4 weeks later) that the lockdown measures from mid-to-late March came too late to prevent an unanticipated number of excess deaths:

‘SAGE advises that surveillance measures, which commenced this week, will provide

actionable data to inform HMG efforts to contain and mitigate spread of Covid-19’ … PHE’s surveillance approach provides sufficient sensitivity to detect an outbreak in its early stages. This should provide evidence of an epidemic around 9- 11 weeks before its peak … increasing surveillance coverage beyond the current approach would not significantly improve our understanding of incidence’ (25.2.20: 1)

It also seems clear from the minutes and papers that SAGE highlighted a reasonable worst case scenario on 26.2.20. It was as worrying as the Imperial College COVID-19 Response Team report dated 16.3.20 that allegedly changed the UK Government’s mind on the 16^th March. Meeting paper 26.2.20a described the assumption of an 80% infection attack rate and 50% clinical attack rate (i.e. 50% of the UK population would experience symptoms), which underpins the assumption of 3.6 million requiring hospital care of at least 8 days (11% of symptomatic), and 541,200 requiring ventilation (1.65% of symptomatic) for 16 days. While it lists excess deaths as unknown, its 1% infection mortality rate suggests 524,800 deaths. This RWC replaces a previous projection (in Meeting paper 10.2.20a: 1-3, based on pandemic flu assumptions) of 820,000 excess deaths (27.2.20: 1).

As such, the more important difference could come from SAGE’s discussion of ‘non-pharmaceutical interventions (NPIs)’ if it recommends ‘mitigation’ while the Imperial team recommends ‘suppression’. However, the language to describe each approach is too unclear to tell (see Theme 1. The language of intervention; also note that NPIs were often described from March as ‘behavioural and social interventions’ following an SPI-B recommendation, Meeting paper 3.2.20: 1, but the language of NPI seems to have stuck).

March 2020

In March, SAGE focused initially (Meetings 12-14) on preparing for the peak of infection on the assumption that it had time to transition towards a series of isolation and social distancing measures that would be sustainable (and therefore unlikely to contribute to a second peak if lifted too soon). Early meetings and meeting papers express caution about the limited evidence for intervention and the potential for their unintended consequences. This approach began to change somewhat from mid-March (Meeting 15), and accelerate from Meetings 16-18, when it became clear that incidence and virus transmission were much larger than expected, before a new phase began from Meeting 19 (after the UK lockdown was announced on the 23^rd).

Meeting 12 (3.3.18) describes preparations to gather and consolidate information on the epidemic and the likely relative effect of each intervention, while its meeting papers emphasise:

‘It is highly likely that there is sustained transmission of COVID-19 in the UK at present’, and a peak of infection ‘might be expected approximately 3-5 months after the establishment of widespread sustained transmission’ (SPI-M Meeting paper 2.3.20: 1)
the need the prepare the public while giving ‘clear and transparent reasons for different strategies’ and reducing ambiguity whenever giving guidance (SPI-B Meeting paper 3.2.20: 1-2)
The need to combine different measures (e.g. school closure, self-isolation, household isolation, isolating over-65s) at the right time; ‘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’ (Meeting paper 4.3.20a: 3).

Meeting 13 (5.3.20) describes staying in the ‘containment’ phase (which, I think, means isolating people with positive tests at home or in hospital) , and introducing: a 12-week period of individual and household isolation measures in 1-2 weeks, on the assumption of 50% compliance; and a longer period of shielding over-65s 2 weeks later. It describes ‘no evidence to suggest that banning very large gatherings would reduce transmission’, while closing bars and restaurants ‘would have an effect, but would be very difficult to implement’, and ‘school closures would have smaller effects on the epidemic curve than other options’ (5.3.20: 1). Its SPI-B Meeting paper (4.3.20b) expresses caution about limited evidence and reliance on expert opinion, while identifying:

potential displacement problems (e.g. school closures prompt people to congregate elsewhere, or be looked after by vulnerable older people, while parents to lose the chance to work)
the visibility of groups not complying
the unequal impact on poorer and single parent families of school closure and loss of school meals, lost income, lower internet access, and isolation
how to reduce discontent about only isolating at-risk groups (the view that ‘explaining that members of the community are building some immunity will make this acceptable’ is not unanimous) (4.3.20b: 2).

Meeting 14 (10.3.20) states that the UK may have 5-10000 cases and ‘10-14 weeks from the epidemic peak if no mitigations are introduced’ (10.3.20: 2). It restates the focus on isolation first, followed by additional measures in April, and emphasizes the need to transition to measures that are acceptable and sustainable for the long term:

‘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’ …’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)

Meeting 15 (13.3.20: 1) describes an update to its data, suggesting ‘more cases in the UK than SAGE previously expected at this point, and we may therefore be further ahead on the epidemic curve, but the UK remains on broadly the same epidemic trajectory and time to peak’. It states that ‘household isolation and social distancing of the elderly and vulnerable should be implemented soon, provided they can be done well and equitably’, noting that there are ‘no strong scientific grounds’ to accelerate key measures but ‘there will be some minor gains from going early and potentially useful reinforcement of the importance of taking personal action if symptomatic’ (13.3.20: 1) and ‘more intensive actions’ will be required to maintain NHS capacity (13.3.20: 2).

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On the 16^th March, the UK Prime Minister Boris Johnson describes an ‘emergency’ (one week before declaring a ‘national emergency’ and UK-wide lockdown)

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Meeting 16 (16.3.20) describes the possibility that there are 5-10000 new cases in the UK (there is great uncertainty on the estimate’), doubling every 5-6 days. Therefore, to stay within NHS capacity, ‘the advice from SAGE has changed regarding the speed of implementation of additional interventions. SAGE advises that there is clear evidence to support additional social distancing measures be introduced as soon as possible’ (16.3.20: 1). SPI-M Meeting paper (16.3.20: 1) describes:

‘a combination of case isolation, household isolation and social distancing of vulnerable groups is very unlikely to prevent critical care facilities being overwhelmed … it is unclear whether or not the addition of general social distancing measures to case isolation, household isolation and social distancing of vulnerable groups would curtail the epidemic by reducing the reproduction number to less than 1 … the addition of both general social distancing and school closures to case isolation, household isolation and social distancing of vulnerable groups would be likely to control the epidemic when kept in place for a long period. SPI-M-O agreed that this strategy should be followed as soon as practical’

Meeting 17 (18.3.20) marks a major acceleration of plans, and a de-emphasis of the low-certainty/ beware-the-unintended-consequences approach of previous meetings (on the assumption that it was now 2-4 weeks behind Italy). It recommends school closures as soon as possible (and it, and SPIM Meeting paper 17.3.20b, now downplays the likely displacement effect). It focuses particularly on London, as the place with the largest initial numbers:

‘Measures with the strongest support, in terms of effect, were closure of a) schools, b) places of leisure (restaurants, bars, entertainment and indoor public spaces) and c) indoor workplaces. … Transport measures such as restricting public transport, taxis and private hire facilities would have minimal impact on reducing transmission’ (18.3.20: 2)

Meeting 18 (23.3.20) states that the R is higher than expected (2.6-2.8), requiring ‘high rates of compliance for social distancing’ to get it below 1 and stay under NHS capacity (23.3.20: 1). There is an urgent need for more community testing/ surveillance (and to address the global shortage of test supplies). In the meantime, it needs a ‘clear rationale for prioritising testing for patients and health workers’ (the latter ‘should take priority’) (23.3.20: 3) Closing UK borders ‘would have a negligible effect on spread’ (23.3.20: 2).

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The lockdown. On the 23^rd March 2020, the UK Prime Minister Boris Johnson declared: ‘From this evening I must give the British people a very simple instruction – you must stay at home’. He announced measures to help limit the impact of coronavirus, including police powers to support public health, such as to disperse gatherings of more than two people (unless they live together), close events and shops, and limit outdoor exercise to once per day (at a distance of two metres from others).

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Meeting 19 (26.3.20) follows the lockdown. SAGE describes its priorities if the R goes below 1 and NHS capacity remains under 100%: ‘monitoring, maintenance and release’ (based on higher testing); public messaging on mass testing and varying interventions; understanding nosocomial transmission and immunology; clinical trials (avoiding hasty decisions’ on new drug treatment in absence of good data) and ‘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). The optimistic scenario is 10,000 deaths from the first wave (SPIM-O Meeting paper 25.3.20: 4).

Meeting 20 Confirms RWC and optimistic scenarios (Meeting paper 25.3.20), but it needs a ‘clearer narrative, clarifying areas subject to uncertainty and sensitivities’ and to clarify that scenarios (with different assumptions on, for example, the R, which should be explained more) are not predictions (29.3.20).

Meeting 21 seeks to establish SAGE ‘scientific priorities’ (e.g. long term health impacts of COVID-19, including socioeconomic impact on health (including mental health), community testing, international work (‘comorbidities such as malaria and malnutrition) (31.3.20: 1-2). NHS to set up an interdisciplinary group (including science and engineering) to ‘understand and tackle nosocomial transmission’ in the context of its growth and urgent need to define/ track it (31.3.20: 1-2). SAGE to focus on testing requirements, not operational issues. It notes the need to identify a single source of information on deaths.

April 2020

The meetings in April highlight four recurring themes.

First, it stresses that it will not know the impact of lockdown measures for some time, that it is too soon to understand the impact of releasing them, and there is high risk of failure: ‘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; see also 14.4.20: 1-2). This problem remains even if a reliable testing and contact tracing system is in place, and if there are environmental improvements to reduce transmission (by keeping people apart).

Second, it notes signals from multiple sources (including CO-CIN and the RCGP) on the higher risk of major illness and death among black people, the ongoing investigation of higher risk to ‘BAME’ health workers (16.4.20), and further (high priority) work on ‘ethnicity, deprivation, and mortality’ (21.4.20: 1) (see also: Race, ethnicity, and the social determinants of health).

Third, it highlights the need for a ‘national testing strategy’ to cover NHS patients, staff, an epidemiological survey, and the community (2.4.20). The need for far more testing is a feature of almost every meeting (see also The need to ramp up testing).

Fourth, SAGE describes the need for more short and long-term research, identifying nosocomial infection as a short term priority, and long term priorities in areas such as the long term health impacts of COVID-19 (including socioeconomic impacts on physical and mental health), community testing, and international work (31.3.20: 1-2).

Finally, it reflects shifting advice on the precautionary use of face masks. Previously, advisory bodies emphasized limited evidence of a clear benefit to the wearer, and worried that public mask use would reduce the supply to healthcare professionals and generate a false sense of security (compare with this Greenhalgh et al article on the precautionary principle, the subsequent debate, and work by the Royal Society). Even by April: ‘NERVTAG concluded that the increased use of masks would have minimal effect’ on general population infection (7.4.20: 1), while the WHO described limited evidence that facemasks are beneficial for community use (9.4.20). Still, general face mask use but could have small positive effect, particularly in ‘enclosed environments with poor ventilation, and around vulnerable people’ (14.4.20: 2) and ‘on balance, there is enough evidence to support recommendation of community use of cloth face masks, for short periods in enclosed spaces where social distancing is not possible’ (partly because people can be infectious with no symptoms), as long as people know that it is no substitute for social distancing and handwashing (21.4.20)

May 2020

In May, SAGE continues to discuss high uncertainty on relaxing lockdown measures, the details of testing systems, and the need for research.

Generally, it advises that relaxations should not happen before there is more understanding of transmission in hospitals and care homes, and ‘until effective outbreak surveillance and test and trace systems are up and running’ (14.5.20). It advises specifically ‘against reopening personal care services, as they typically rely on highly connected workers who may accelerate transmission’ (5.5.20: 3) and warns against the too-quick introduction of social bubbles. Relaxation runs the risk of diminishing public adherence to social distancing, and to overwhelm any contact tracing system put in place:

‘SAGE participants reaffirmed their recent advice that numbers of Covid-19 cases remain high (around 10,000 cases per day with wide confidence intervals); that R is 0.7-0.9 and could be very close to 1 in places across the UK; and that there is very little room for manoeuvre especially before a test, trace and isolate system is up and running effectively. It is not yet possible to assess the effect of the first set of changes which were made on easing restrictions to lockdown’ (28.5.20: 3).

It recommends extensive testing in hospitals and care homes (12.5.20: 3) and ‘remains of the view that a monitoring and test, trace & isolate system needs to be put in place’ (12.5.20: 1)

June 2020

In June, SAGE identifies the importance of clusters of infection (super-spreading events) and the importance of a contact tracing system that focuses on clusters (rather than simply individuals) (11.6.20: 3). It reaffirms the value of a 2-metre distance rule. It also notes that the research on immunology remains unclear, which makes immunity passports a bad idea (4.6.20).

It describes the result of multiple meeting papers on the unequal impact of COVID-19:

‘There is an increased risk from Covid-19 to BAME groups, which should be urgently investigated through social science research and biomedical research, and mitigated by policy makers’ … ‘SAGE also noted the importance of involving BAME groups in framing research questions, participating in research projects, sharing findings and implementing recommendations’ (4.6.20: 1-3)

The full list of SAGE posts:

COVID-19 policy in the UK: yes, the UK Government did ‘follow the science’

Did the UK Government ‘follow the science’? Reflections on SAGE meetings

The overall narrative underpinning SAGE advice and UK government policy

SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions

COVID-19 policy in the UK: Table 2: Summary of SAGE minutes, January-June 2020

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Filed under COVID-19, Evidence Based Policymaking (EBPM), Prevention policy, Public health, public policy, UK politics and policy

July 8, 2020 · 8:19 am

COVID-19 policy in the UK: The role of SAGE and science advice to government

This post is part 2 of COVID-19 policy in the UK: Did the UK Government ‘follow the science’? Reflections on SAGE meetings

The issue of science advice to government, and the role of SAGE in particular, became unusually high profile in the UK, particularly in relation to four factors:

Ministers described ‘following the science’ to project a certain form of authority and control.
The SAGE minutes and papers – including a record of SAGE members and attendees – were initially unpublished, in line with the previous convention of government to publish after, rather than during, a crisis.

‘SAGE is keen to make the modelling and other inputs underpinning its advice available to the public and fellow scientists’ (13.3.20: 1)

When it agrees to publish SAGE papers/ documents, it stresses: ‘It is important to demonstrate the uncertainties scientists have faced, how understanding of Covid-19 has developed over time, and the science behind the advice at each stage’ (16.3.20: 2)

‘SAGE discussed plans to release the academic models underpinning SAGE and SPI-M discussions and judgements. Modellers agreed that code would become public but emphasised that the effort to do this immediately would distract from other analyses. It was agreed that code should become public as soon as practical, and SPI-M would return to SAGE with a proposal on how this would be achieved. ACTION: SPI-M to advise on how to make public the source code for academic models, working with relevant partners’ (18.3.20: 2).

SAGE welcomes releasing names of SAGE participants (if willing) and notes role of Ian Boyd as ‘independent challenge function’ (28.4.20: 1)

SAGE also describes the need for a better system to allow SAGE participants to function effectively and with proper support (given the immense pressure/ strain on their time and mental health) (7.5.20: 1)

There were growing concerns that ministers would blame their advisers for poor choices (compare Freedman and Snowdon) or at least use science advice as ‘an insurance policy’, and
There was some debate about the appropriateness of Dominic Cummings (Prime Minister Boris Johnson’s special adviser) attending some meetings.

Therefore, its official description reflects its initial role plus a degree of clarification on the role of science advice mechanisms during the COVID-19 pandemic. The SAGE webpage on the gov.uk sites describes its role as:

‘provides scientific and technical advice to support government decision makers during emergencies … SAGE is responsible for ensuring that timely and coordinated scientific advice is made available to decision makers to support UK cross-government decisions in the Cabinet Office Briefing Room (COBR). The advice provided by SAGE does not represent official government policy’.

Its more detailed explainer describes:

‘SAGE’s role is to provide unified scientific advice on all the key issues, based on the body of scientific evidence presented by its expert participants. This includes everything from latest knowledge of the virus to modelling the disease course, understanding the clinical picture, and effects of and compliance with interventions. This advice together with a descriptor of uncertainties is then passed onto government ministers. The advice is used by Ministers to allow them to make decisions and inform the government’s response to the COVID-19 outbreak …

The government, naturally, also considers a range of other evidence including economic, social, and broader environmental factors when making its decisions…

SAGE is comprised of leading lights in their representative fields from across the worlds of academia and practice. They do not operate under government instruction and expert participation changes for each meeting, based on the expertise needed to address the crisis the country is faced with …

SAGE is also attended by official representatives from relevant parts of government. There are roughly 20 such officials involved in each meeting and they do not frequently contribute to discussions, but can play an important role in highlighting considerations such as key questions or concerns for policymakers that science needs to help answer or understanding Civil Service structures. They may also ask for clarification on a scientific point’ (emphasis added by yours truly).

Note that the number of participants can be around 60 people, which is more like an assembly with presentations and a modest amount of discussion, than a decision-making function (the Zoom meeting on 4.6.20 lists 76 participants). Even a Cabinet meeting is about 20 and that is too much for coherent discussion/ action (hence separate, smaller, committees).

Further, each set of now-published minutes contains an ‘addendum’ to clarify its operation. For example, its first minutes in 2020 seek to clarify the role of participants. Note that the participants change somewhat at each meeting (see the full list of members/ attendees), and some names are redacted. Dominic Cummings’ name only appears (I think) on 5.3.20, 14.4.20, and two meetings on 1.5.20 (although, as Freedman notes, ‘his colleague Ben Warner was a more regular presence’).

More importantly, the minutes from late February begin to distinguish between three types of potential science advice:

to describe the size of the problem (e.g. surveillance of cases and trends, estimating a reasonable worst case scenario)
to estimate the relative impact of many possible interventions (e.g. restrictions on travel, school closures, self-isolation, household quarantine, and social distancing measures)
to recommend the level and timing of state action to achieve compliance in relation to those interventions.

SAGE focused primarily on roles 1 and 2, arguing against role 3 on the basis that state intervention is a political choice to be taken by ministers. Ministers are responsible for weighing up the potential public health benefits of each measure in relation to their social and economic costs (see also: The relationship between science, science advice, and policy).

Example 1: setting boundaries between advice and strategy

‘It is a political decision to consider whether it is preferable to enact stricter measures at first, lifting them gradually as required, or to start with fewer measures and add further measures if required. Surveillance data streams will allow real-time monitoring of epidemic growth rates and thus allow approximate evaluation of the impact of whatever package of interventions is implemented’ (Meeting paper 26.2.20b: 1)

This example highlights a limitation in performing role 2 to inform 3: SAGE would not be able to compare the relative impact of measures without knowing their level of imposition and its impact on compliance. Further, the way in which it addressed this problem is crucial to our interpretation and evaluation of the timing and substance of the UK government’s response.

In short, it simultaneously assumed away and maintained attention to this problem by stating:

‘The measures outlined below assume high levels of compliance over long periods of time. This may be unachievable in the UK population’ (26.2.20b: 1).
‘advice on interventions should be based on what the NHS needs and what modelling of those interventions suggests, not on the (limited) evidence on whether the public will comply with the interventions in sufficient numbers and over time’ (16.3.20: 1)

The assumption of high compliance reduces the need for SAGE to make distinctions between terms such as mitigation versus suppression (see also: Confusion about the language of intervention and stages of intervention). However, it contributes to confusion within wider debates on UK action (see Theme 1. The language of intervention).

Example 2: setting boundaries between advice and value judgements

‘SAGE has not provided a recommendation of which interventions, or package of interventions, that Government may choose to apply. Any decision must consider the impacts these interventions may have on society, on individuals, the workforce and businesses, and the operation of Government and public services’ (Meeting paper 4.3.20a: 1).

To all intents and purposes, SAGE is noting that governments need to make value-based choices to:

Weigh up the costs and benefits of any action (as described by Layard et al, with reference to wellbeing measures and the assumed price of a life), and
Decide whose wellbeing, and lives, matter the most (because any action or inaction will have unequal consequences across a population).

In other words, policy analysis is one part evidence and one part value judgement. Both elements are contested in different ways, and different questions inform political choices (e.g. whose knowledge counts versus whose wellbeing counts?).

[see also:

‘Determining a tolerable level of risk from imported cases requires consideration of a number of non-science factors and is a policy question’ (28.4.20: 3)
‘SAGE reemphasises that its own focus should always be on providing clear scientific advice to government and the principles behind that advice’ (7.5.20: 1)]

Future reflections

Any future inquiry will be heavily contested, since policy learning and evaluation are political acts (and the best way to gather and use evidence during a pandemic is highly contested). Still, hopefully, it will promote reflection on how, in practice, governments and advisory bodies negotiate the blurry boundary between scientific advice and political choice when they are so interdependent and rely so heavily on judgement in the face of ambiguity and uncertainty (or ‘radical uncertainty’). I discuss this issue in the next post, which highlights the ways in which UK ministers relied on SAGE (and advisers) to define the policy problem.

The full list of SAGE posts:

COVID-19 policy in the UK: yes, the UK Government did ‘follow the science’

Did the UK Government ‘follow the science’? Reflections on SAGE meetings

The overall narrative underpinning SAGE advice and UK government policy

SAGE Theme 2. Limited capacity for testing, forecasting, and challenging assumptions