1.1 The COVID-19 epidemic in the UK
By August 2021, the original strain of SARS-CoV2 first identified in Wuhan, China had been replaced in circulation by a number of ‘variants of concern’ (VOC), designated by the World Health Organisation (WHO) as variants with one or more of the following characteristics:
- increased transmissibility
- more severe disease
- reduced effectiveness of treatments or vaccines
- failure to be detected by current diagnostic tests.
The new variants were designated by Greek letters (Figure 1), and as of August 2021, the delta variant accounted for nearly 99% of the cases in the UK.
At this time point the incidence of infection, which had been low during the spring and early summer was starting to rise in the community, as demonstrated in Figure 2. If you want to learn more about the course of the pandemic in the UK, all data during this period is available from Public Health England, and since December 2021, from the Health Security Agency.
