In late November last year, epidemiologists began noticing some unusual patterns in the spread of COVID-19 in the South East of England
A national lockdown had been in place since the start of the month, yet despite initial drop offs, cases in parts of Kent, Essex and London had started to increase again.
The problem was flagged to a small team of PHE scientists and external academics in the specialised field of viral genomics – the study of a virus’s genetic make-up.
They began looking at cases that had undergone sequencing (genetic analysis) across Kent. What they saw was lots of cases of a new variant that featured high numbers of unusual mutations.
Unbeknownst to the team at the time, this variant would set off on a rapid expansion across the South East of England, eventually taking over as the dominant COVID-19 strain in the UK and spreading to over 100 countries.
The investigation begins
Doctor Meera Chand, one of the national COVID-19 incident directors at PHE, and Richard Myers, Head of Bioinformatics at PHE, were among the first to become aware of the new variant, then known as B.1.1.7, and were part of the team tasked with quickly understanding what the UK was dealing with.
We immediately knew we had found something very concerning”, says Meera. “Normally when you’re looking at samples you would expect to see lots of small clusters made up of multiple strains that are all slightly different. But when we looked at Kent, we saw about 50% of the samples were extremely similar, forming one massive cluster.
Richard adds: “It was quite unusual. Up to that point, the virus had been characterised by having a relatively slow mutational rate, maybe two variations a month. Suddenly out of nowhere we’ve got this large cluster featuring mutations that were significantly different to what we’d looked at before.”
Sourch: https://publichealthmatters.blog.gov.uk/2021/04/22/disease-detectives-finding-the-uks-dominant-covid-19-variant-and-the-race-to-understand-its-impact/
