How the UK variant of the coronavirus spread across the world - Reuters UK

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It started as a single genetic sample in a British database of many thousands.

Scientists at Britain’s COVID-19 Genomics UK Consortium (COG-UK) first detected the B.1.1.7 variant of coronavirus in September in the English county of Kent. It took almost three months before they discovered that the “Kent variant” was 70% more transmissible than existing variants, and further weeks before another shocking discovery: It was also much deadlier.

The coronavirus has undergone thousands of mutations since its emergence in 2019, but most make no difference to its impact on human health. But B.1.1.7 – also known as VOC (“variant of concern”) 202012/01 – drove a surge in cases that flooded Britain’s hospitals, pushed its death toll above 125,000, and triggered travel bans by dozens of countries.

The Kent variant has now gone global. Elsewhere in Europe, it has fuelled third waves of the pandemic that have triggered lockdowns and threaten to outpace sluggish vaccination programs. The Kent variant will be the dominant strain in the United States by the end of this month, say experts, who warn the country to brace for impact and not – as some states have – loosen restrictions.

The rise of the UK variant in Britain

Weekly breakdown of about 230,000 virus samples

A Reuters analysis of almost 230,000 samples shows how B.1.1.7 dramatically increased to overtake the previously dominant “GV” strain.

Where it all began

The first case of B.1.1.7 was detected elsewhere in Kent, but the variant first took hold on the Isle of Sheppey – a flat, marshy island on the estuary of the River Thames – and its borough of Swale. Sheppey had been barely touched by the pandemic’s first wave last spring, but in October the virus began spreading rapidly across the island. For most of November, England was under a second national lockdown, but cases in Kent continued to surge. Only later did scientists realise that B.1.1.7 was so transmissible it was leap-frogging the restrictions.

Medway Maritime Hospital in Gillingham, which serves Sheppey and the rest of populous northern Kent, bore the initial brunt of B.1.1.7. In the first two weeks of November, the number of Covid patients at the hospital doubled. Medway Maritime would soon become the busiest Covid hospital in Britain, with almost half of its adult general and acute-care beds occupied by patients with the disease.

From trickle to torrent

The COVID-19 Genomics UK Consortium (COG-UK) tracks mutations in the coronavirus by sequencing, or “reading,” their complete set of genetic instructions, or genomes. COG-UK sequences thousands of samples every week, allowing us to trace how B.1.1.7 spread across Britain.

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