Coronavirus (COVID-19) protective measures: indicators and data

Indicators

When the Strategic Framework was initially published in October 2020 introducing the five Protection Levels, a decision framework was presented which set out how data and intelligence is used to inform decisions applying the levels to local geographies. This included a basket of indicators drawing on local data.

Data related to the epidemic in Scotland were used to create five core indicators.  These were used to produce an indicator report, in conjunction with other relevant facts and circumstances, to inform discussions on the level-setting process up until December 2020.  Drawing upon clinical advice, health planning and the views of the National Incident Management Team data group, it was proposed that the indicator definitions be revised.  The core indicators and their definitions are described in Table 2 and also in more detail in the annex.

Core indicators 

It is important to note that the first two indicators are backward-looking – they reflect what happened in the past due to the lagged impact of past decisions and other factors.  However, when we look ahead, we are interested in what we think future changes to restrictions and other factors would do to the virus in an area: what has happened in the past is only a limited guide to what will happen in the future, particularly as new variants arise which may be more transmissible.  In other words, low case numbers now do not automatically mean that restrictions should be eased.  Instead, it is important to consider whether case numbers would remain suppressed, under the restrictions we are putting in place, if the virus was imported into an area.  This question is particularly important for areas of low incidence as travel increases and settings re-open and activities resume.  In this context forecasts play a key role – taking account of future changes in restrictions and of other relevant factors, particularly vaccination rates which would render outbreaks less harmful.

Along with the five core indicators, secondary indicators and broader considerations on health will be considered (see Table 3).  The economic and social impacts of any Level decisions will also draw on the insights of local partners and stakeholders and data such as that found on the Four Harms Dashboard. This quantitative and qualitative information will allow for transparent, reliable and consistent decision-making when setting Levels.  These indicators depend on a combination of routine data, as well as forecasts based on these data.  They might also include subjective judgements on hard-to-measure indicators such as the level of adherence with the regulations.  This is not an exhaustive or static list of all potential indicators, we will continue to draw upon the latest developments in science and technology to monitor the epidemic.

Secondary indicators

The aim of these indicators is to capture a reliable and robust view of current and projected local conditions in relation to health system capacity and transmission.  These will sit alongside other intelligence in informing decision making concerning the placing or lifting of restrictions. This is consistent with the approach of the WHO.  Such an approach supports transparent and consistent assessment to inform decision making that is able to respond swiftly whilst taking cognisance of wider uncertainties and science.

The decision-making for Levels allocation draws in part on numerical thresholds for a set of indicators.  The WHO thresholds that were published in the Strategic Framework Update in February 2021 remain helpful and are set out in Table 4 below.  It is important to remember that indicators and thresholds serve as one of a number of considerations, rather than being used in a rigid way.  The overall context in an area, including the delivery of the outbreak management response and the success of the vaccination programme, as well as further scientific evidence around vaccine efficacy, will always be crucial.  Situations may arise, such as the growing presence of vaccine-resistant mutations and new variants of concern both within Scotland and other countries, where the role of judgement in decision making remains central, supported by evidence, analysis, and local intelligence. 

WHO thresholds