A‘super-seeding’ event in the UK helped spreading the COVID-19 alpha variant

The rapid spread of the Alpha variant of COVID-19 resulted from biological changes in the virus and was enhanced by large numbers of infected people ‘exporting’ the variant to multiple parts of the UK in a ‘super-seeding’ event, according to a research article that appeared in Science this week. Lead author of the study is Branco Weiss Fellow Dr Moritz Kraemer in Oxford’s Department of Zoology. He says: “At the beginning of December 2020 the epicentre of COVID-19 transmission in England shifted rapidly from the North West and North East to London and the South East, as the Alpha variant took hold. As people travelled from London and the South East to other areas of the UK they ‘seeded’ new transmission chains of the variant. This continued as a national ‘super-seeding’ event which did not start to slow until early January.”

The results of the largest phylogeographic analysis ever conducted map the spread of the variant (also known as lineage B.1.1.7) from its origins in Kent and Greater London in November 2020 to all but five counties in Wales, Scotland, Northern Ireland and England by 19 January. The rapid spread of the Alpha variant across the UK led to initial reports that it could be up to 80% more transmissible than the original strain. The most recent study, however, shows that mobility significantly affected its spread and early growth rates. According to the researchers, this highlights the need for epidemiologists to work closely with virologists and geneticists rapidly to create accurate transmissibility estimates for new variants.