The British authorities said on Friday that they are considering changing vaccination protocols and reintroducing local lockdowns to stem the spread of a coronavirus variant first detected in India, a warning sign for countries that are easing restrictions even though their own vaccination campaigns are incomplete.
The numbers of cases involving the variant, known as B.1.617, rose from 520 last week to 1,313 cases this week in Britain, according to official statistics.
The extent to which the variant has spread globally is unclear, because most countries lack the genomic surveillance capabilities employed in England.
That surveillance capability has allowed health officials in Britain to spot the rise of concerning variants more quickly than other nations, offering an early warning system of sorts as a variant seen in one nation almost invariably pops up in others.
might not be quite as effective against B.1.617. The agency said, however, that vaccines were likely to remain potent enough to provide protection from serious illness and death.
British officials have said the variant appears to be more contagious than one detected last year in Kent, southeast of London, which swept across Britain in the winter, forcing the country into one of the world’s longest national lockdowns. The British variant has now been found in countries around the world.
The variant first detected in India has been found in virus sample from 44 countries, the W.H.O. said this week.
The U.N. agency has designated the B.1.617 variant as a variant of concern.
Christina Pagel, a member of a group of scientists advising the government, known as SAGE, said postponing next week’s reopening would avoid “risking more uncertainty, more damaging closures and longer recovery from a worse situation.”
“We need to learn from previous experience,” Dr. Pagel, the director of the Clinical Operational Research Unit at University College London, said on Twitter.
Britain briefly reopened its economy at the end of last year, only to abruptly impose new restrictions that remained in place for months as it fought a deadly wave of infections.