Predicted COVID-19 positive cases, hospitalisations, and deaths associated with the Delta variant of concern, June–July, 2021 (EURO 2020)

July 2021: A research letter in The Lancet Digital Health models the impact of the Delta variant on COVID-19 cases, hospital admissions and deaths in Scotland around the time of EURO 2020.

Summary in Plain English

The UEFA European Football Championship (EURO 2020) took place between 11 June and 11 July 2021 after being postponed from last year. It featured the largest crowds of any sporting event seen in the UK for 15 months, with football fans travelling from across the UK and overseas to attend.

Public Health England reported that the Delta variant became the UK’s most common strain of SARS-COV-2 on 3 June 2021.

Find out more about variants in the UK [UKGov]

Why did we carry out this research?

Evidence has shown that large gatherings can cause ‘super-spreader’ events. Data have also shown that the Delta variant causes higher case numbers and more severe disease than other strains of SARS-CoV-2.

We wanted to understand the impact of the Delta variant on COVID-19 cases, hospital admissions and deaths in Scotland as a result of increased movement around the time of EURO 2020. To do this, we updated our existing model and looked at data from 99% of the Scottish population up to 19 June 2021.

We used this data to make predictions about COVID-19 cases, hospital admissions and deaths from 20 June until 19 July 2021.

What does our model include?

Our model now factors in important details like an increasing number of infections with the Delta variant, variations in the number of vaccinated people over time, school closures, and the impact of a surge in cases around the time of EURO 2020.

In the model we assumed that there would be short-term increasing rates of cases (‘exponential growth’). This doesn’t take into account an individual person’s likelihood of becoming infected with SARS-CoV-2. We set up the model so that excess cases from EURO 2020 wouldn’t add to this exponential growth.

The model uses data from the EAVE II cohort.

Find out more about the orginal model: Temporal trends and forecasting of COVID-19 hospitalisations and deaths in Scotland using a national real-time patient-level data platform: a statistical modelling study | The University of Edinburgh

What did we find in this study?

Best case scenario:

In the best-case scenario that assumed no impact of EURO 2020, our model suggested that there could be 2,751 cases, 97 COVID-19 hospital admissions and seven COVID-19 deaths a day by 19 July.

Worst case scenario:

We found from real data that 1,349 excess cases were happening each day from 20-30 June. We used this value to form a worst-case scenario, assuming the daily excess of cases would continue until 19 July. In this scenario, our model suggested 134 hospital admissions and 10 deaths a day by 19 July.

Comparing modelled and real data:

At the time of publication, real data was available for us to observe until 12 July. The surge in cases peaked earlier than our model predicted. By 19 July, there were 1,908 cases, 75 hospital admissions and 8 deaths per day.

Although our worst case scenario did not come to pass, increased movement and the Delta variant have contributed to a surge in cases. As such, we recommend caution when proceeding to lift lockdown restrictions.

Note

This plain English summary was created with the support and feedback of the EAVE II Patient Advisory Group (PAG). This one in particular was authored by Kamil S.

To learn more about the PAG, see: Our EAVE II Patient Advisory Group (PAG) | The University of Edinburgh