2.1 Succession of variants
Each of the VOCs has gradually replaced previous variants as the dominant strain in the pandemic although this has occurred at different times in different countries. This effect can be seen in the spread of the alpha variant, which was first identified in the UK in Kent in November 2020 from a sample taken in September. The variant spread rapidly in the UK and by January 2021 it accounted for more than half of the identified genomic sequences. By October 2021 it had disappeared from the UK, replaced mostly by the delta variant. By March 2022 the alpha variant was declared to be extinct worldwide (Figure 3).
