Coronavirus (COVID-19): modelling the epidemic (Issue No. 65)

Latest findings in modelling the COVID-19 epidemic in Scotland, both in terms of the spread of the disease through the population (epidemiological modelling) and of the demands it will place on the system, for example in terms of health care requirement

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1. UKHSA has now taken over the role of compiling the consensus from SAGE, based on models which feed into the Epidemiology Modelling Review Group (EMRG).

2. Different data-streams and different models are expected to be lagged in their estimates by different amounts when compared with the true underlying epidemiological situation. This is due to multiple lags such as reporting and delays in the infection processes. However, the consensus combination generally reflects a 2-week lag.

3. Particular care should be taken when interpreting this estimate as it is based on low numbers of cases, hospitalisations, or deaths and / or dominated by clustered outbreaks. It should not be treated as robust enough to inform policy decisions alone.

4. The cyan bars use Covid‑19 test data and purple bars use multiple sources of data. The estimates produced by the Scottish Government are the two on the left. (Yellow uses confirmed cases from PHS; green uses wastewater data).The UKHSA consensus range is the right‑most (red).

5. Deaths, Cases and Hospitalisations from PHS COVID-19 daily cases in Scotland dashboard.

6. Vaccination and contact data for the 0-17 age cohort is not presented due to the vast majority of this age group not being offered vaccinations and the SCS excluding contacts between children.

7. All scenarios are based on current vaccine roll-out plans and efficacy assumptions.

8. The actual positive tests are adjusted to coincide with the estimated day of infection.

9. Actual data does not include full numbers of CPAP. ICU bed actuals include all ICU patients being treated for Covid-19 including those over 28 days.

10. Four week projections are provided here: Scientific evidence supporting the government response to coronavirus (COVID-19) - GOV.UK (

11. The exceptions to this are Moray, Na h-Eileanan Siar, Orkney Islands and Shetland Islands.

12. Numbers are included in Table 1 in the Technical Annex.

13. Across NHS Lanarkshire, coverage fell from 80-90% to about 70%. In this area, the previously identified high level of wastewater Covid-19 fell to levels more similar to the national average (from around 70 to 50 Mgc/p/d), but this was primarily driven by a single low measurement taken at the large site of Daldowie.

14. Anomalously high values, one in Seafield (Edinburgh) in mid-February (see Issue 40), one in Dunblane in mid-June, and two in Daldowie in January, were removed.

15. The black line and red shaded area provide a smoothed curve and confidence interval for WW RNA that is estimated from a generalised additive model based on a Tweedie distribution.

16. Advancements in detection and interpretation practices allow us to identify when outlying results are anomalous rather than indicators of spikes in Covid-19 levels. Table 2 provides population weighted daily averages for normalised WW Covid-19 levels both with and without the outliers removed. See Technical Annex in Issue 60 of these Research Findings for further details.

17. Coverage as at the week beginning 10th August 2021.



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