Coronavirus (COVID-19): Scotland's route map - supporting evidence for the 30 July 2020 Review
This document has been completed by the Scottish Government to inform decisions about timings of changes within Phase 3 as set out at the review point on 30 July 2020.
This document is part of a collection
WHO criterion 1: Evidence shows that COVID-19 transmission is controlled
R is consistently low
Number of infectious cases is showing a sustained decline
The R value for COVID-19 in Scotland was estimated by SAGE to be between 0.6 and 0.9 on 29 July. Scottish Government analysis, using the Imperial College modelling code, is in agreement with this assessment, and suggests it has been below the critical threshold of 1.0 since 23 March. Given the very low prevalence now in Scotland, the R number itself is likely to become less useful as an indicator.
Further Government modelling estimates the most likely number of infectious people in Scotland on 24 July to be 300. This is the seventeenth week in a row there has been a decline in this number, and has fallen by around three quarters from 1200 cases at the end of June (within a range of between 850 and 1600). This number is forecast to continue to fall for the next two weeks.
Further modelled information, including short and medium term forecasts of hospital bed and intensive care requirements, along with the above R-value and infectious cases data will be published in a weekly update every Thursday. It takes time for the virus to take its course, therefore we will not fully see the effect of moving to Phase 3 in our modelling until early August.
The criteria for entering Phase 3 included the number of infectious cases showing a sustained decline. Once the virus has been suppressed to very low levels it becomes harder to sustain further declines. At very low numbers, some volatility in the number of cases would be expected but we will need to remain vigilant for any sustained increase.
Supplementary measures
Confirmed COVID-19 cases in Scotland by day
The number of new confirmed COVID-19 cases by specimen date showed a sustained decline since peaking in late April 2020, based on the 7 day moving average, up until 9 July, even in the context of increased testing and expanded eligibility. However in the last 2 weeks we have seen a slight increase in confirmed cases – potentially as a result of increased detection of asymptomatic cases through Test & Protect, but also highlighting that the virus is persisting in Scotland.
Graph Description
The graph shows the moving average of new cases by when the test specimen was taken. The graph rises quickly throughout March, to around 350 new cases a day throughout April. A regular decline begins around the 10th of May, falling to 50 or fewer new cases a day by the 7th of June. There has been a slight increase in confirmed cases over the last 2 weeks.
Source: Public Health Scotland 26 July 2020
Hospital admissions by day where COVID-19 is confirmed
The number of hospital admissions per day for those with a positive COVID-19 result has shown a sustained decline since 7 April 2020, based on the 7 day moving average. From 25 June – 15 July there was on average 1 admission per day.
Graph Description
This shows the number of people admitted to hospital with confirmed covid-19, since the start of March, including a 7-day moving average. It rises to around 200 a day by the end of March, before declining rapidly throughout April. From the 19th of April, fewer than 100 people a day were admitted to hospital with confirmed covid-19. This decline has continued during May and June. From 25th June there was on average 1 admission per day.
Source: COVID-19 Statistical Report, Public Health Scotland 22 July 2020
ICU admissions by day of admission to Unit for those where COVID-19 is confirmed
The number of new daily ICU admissions showed a sustained decline since 4 April based on the 7 day moving average, and has been at low levels since early May. From 10 – 19 July 2020, there were 0 confirmed COVID-19 patients admitted to ICU.
Graph Description
This graph broadly follows the shape of hospital admissions: a rapid rise during March, up to around 25 admissions a day at the start of April, before declining rapidly to less than 10 new admissions a day in the last two weeks of April. This trend has continued since, with 2 or fewer new admissions a day since the 10th of May and from 10 July there were 0 confirmed COVID-19 patients admitted to ICU.
Source: COVID-19 Statistical Report, Public Health Scotland 22 July 2020
Deaths by week of registration Scotland
There has been a sustained decline in the number of weekly deaths where COVID-19 is recorded on the death certificate. The number of COVID-19 deaths peaked in Week 17 (20 April to 26 April 2020). Six deaths were registered in the week up to Sunday 19 July, a decrease of 7 from the previous week. Overall, the number of deaths has been around the expected level for the last 6 weeks.
Graph Description
There are three lines on this chart: all deaths in 2020, the average of all deaths in the previous 5 years, and the number of Covid-19 deaths in 2020. These are all presented by week of registration. The number of deaths by week in 2020 is at the 5-year average around 1,100 in week 13. It then grows rapidly, peaking at 2,000 deaths in week 15. Deaths in 2020 then decline slowly. In week 20, there were 1,421 deaths in 2020, compared to the 5-year average of 1,064. Now, in week 27, all 2020 deaths are at 978, compared to a 5-year average of 1,018. The shape of the Covid-19 deaths mirrors the growth of ‘all 2020 deaths’ – rising from week 12, to a peak in week 17, before declining steadily. In the latest week, week 27, there were 17 COVID-19 deaths recorded.
Source: Deaths involving coronavirus (COVID-19) in Scotland, NRS 22 July 2020
https://www.nrscotland.gov.uk/covid19stats
Test result for those who have symptoms in community % by week
The proportion of those who have a positive test for COVID-19 out of those who are symptomatic of COVID-19 in community healthcare has been steadily decreasing since week 16 (13 to 19 April). The weekly swab positivity rate has now been at 0.0% for 3 weeks
Graph Description
This graph shows the percentage of positive swab tests taken as part of community surveillance, along with 95% confidence intervals. In week 16, around 10% of swabs tested positive for COVID-19, with an upper-95% confidence interval of more than 20%. The weekly swab positivity rate has now been at 0.0% for 3 weeks.
Source: Enhanced Surveillance data, Public Health Scotland
Note: Confidence intervals wide in the pilot phase of weeks 16 and 17 due to small numbers
In conclusion:
There is a continued and sustained decline in prevalence of COVID-19 in Scotland.
The number of positive cases has risen slightly over the last two weeks indicating the risk of Covid re-emerging remains present. The evidence for the impact of the early Phase 3 changes will only be available in early August.
On the basis of the evidence summarised above the assessment is that this Phase 3 criterion continues to be met at this review point.
Contact
Email: covidexitstrategy@gov.scot
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