Global concern

Globally, there are now four VOCs – B.1.617, B.1.1.7 (first seen in the UK), B.1.351 (first recorded in South Africa) and P.1 (first seen in Brazil). Of these, the variant from UK demonstrated a transmission advantage unlike any Sars-Cov-2 version before, triggering new waves of infection where it was first seen and in several other European nations. Experts say that the India-linked variant now appears to be outcompeting it in epidemiological terms, which could indicate it to have an evolutionary advantage.

“Tracking frequencies over time in sequence data shared to @gisaid shows a continued increase in B.1.617, while recent weeks have shown a decline in B.1.1.7,” said Trevor Bedford, a scientist at the Fred Hutchinson Cancer Research Center, in a series of tweets analysing the genomic clues.

“The observed rapid growth of this (sub)-lineage in India and elsewhere would suggest that this virus is potentially highly transmissible. If faster growth than B.1.1.7 in India and in the UK is conclusive, it would suggest that this lineage will spread widely,” he added.

Christina Pagel, director of the clinical operational research unit at University College London, said the rise in B.1.617.2 cases was concerning enough to delay the next stage of the UK’s reopening roadmap.

“Under ‘current restrictions’, within a context of [very] infectious B117 (”Kent” variant) and ‘high population immunity’ B.1.617.2 seems to be spreading quickly. Numbers still low(ish) but for how much longer? What will happen after 17th May when so much more opens?” she said in a tweet on May 10, urging the government to step-up surveillance.