Coronavirus (COVID-19): modelling the epidemic (issue no. 46)

Key Points

• The reproduction rate R in Scotland is currently estimated as being between 0.8 and 1.0.
• The number of new daily infections for Scotland is estimated as being between 13 and 31, per 100,000 people. There have been no changes in the estimate this week.
• The growth rate for Scotland is currently estimated as being between -4% and 0%.
• Average contacts have increased compared to two weeks previously, with a current level of 3.2 daily contacts.
• Contacts within the work setting have increased by 49% in the last two weeks, whereas mean contacts in the school setting have decreased by approximately 18%, coinciding with spring holidays.
• The biggest increase in interactions, compared to two weeks previously, has been for those aged 50-59 with individuals under 18.
• Those aged between 50 and 70 have shown the largest increase in contacts in the most recent survey, largely driven by contacts in the work and in the 'other' setting (contacts outside of the school, home or work settings).
• The proportion of people that have visited other people's homes has risen from 27% to 33% in the most recent survey.
• Although there are increases in contacts for those aged over 50, positive Covid-19 cases and deaths for everyone over this age continue to decline.
• Hospital bed and ICU occupancy are projected to fall over the next few weeks, but these both may plateau or increase as a result of schools reopening and other relaxations of non-pharmaceutical interventions.
• Modelled rates per 100K indicate that for the week commencing 18 April 2021, 4 local authorities have at least a 75% probability of exceeding 50 cases, 1 of those has at least a 75% probability of exceeding 100 cases and none of those have at least a 75% probability of exceeding 300 cases. In last week's issue of these Research Findings, 7 local authorities had a 75% or higher probability of exceeding 50 cases per 100K.
• The overall level of wastewater Covid this week was slightly lower than the last few weeks, consistent with a slight fall in the rate of new cases. As before, it appears that smaller sites may often have lower Covid-19 levels than larger sites.