Lessons from the UK about a more-contagious covid-19 variant

3 months ago 5

The U.K. has become a testing ground for how a more-contagious and possibly deadlier coronavirus variant spreads through communities, displacing its less-transmissible ancestors and complicating vaccine rollouts and the lifting of lockdowns.

The variant has now been identified in more than 70 countries and 40 U.S. states, and its advance in Britain could help scientists understand its likely trajectory in the U.S. These charts show the spread of the variant around the U.K. and what British scientists are learning about it—including its higher transmissibility and lethality.

“Increasingly, since this version of the virus was discovered we’ve really been running two separate pandemics," said Jason Leitch, national clinical director for Scotland. “That is a warning to other countries."

British scientists detected the new variant in November, and in early December traced its first appearance in the U.K. to the southern English county of Kent, in September. The country was in lockdown in November to suppress a deadly wave of infection that had been building since the fall. British public health officials were mystified by the virus’s ongoing spread in southern England despite those restrictions.

When scientists examined the variant’s genome, they found an unusually large number of mutations, some of which pointed to the possibility the new variant could spread more rapidly than pre-existing versions. Further sequencing—and a testing quirk that served as a reliable proxy for the variant’s presence—revealed how quickly the variant rose to dominance.

When lockdown lifted in early December, the new variant went national. The overall case rate per 100,000 people increased fivefold in London, and the new variant was soon detected in almost every corner of the U.K. Another, stricter nationwide lockdown was imposed Jan. 4 to arrest its spread. Caseloads have since fallen back and the government has published plans for a staged reopening in the coming months.

Public-health officials began probing the contact patterns of people known to be infected with the new variant, now widely known as B.1.1.7. They found evidence that people infected with the variant went on to infect more people than those infected with the previously dominant strain. That finding reinforced the genetic analysis pointing to a more transmissible version of the pathogen.

“We haven’t seen anything quite like the U.K. variant in terms of its growth rate, in terms of its transmissibility," said Nick Loman, a professor of microbial genomics and bioinformatics at the University of Birmingham.

More worrying still, when public-health officials and teams at U.K. universities began examining clinical data on those known to have been infected with B.1.1.7, they detected signs the variant might be associated with a higher risk of death.

One preliminary analysis, from Scotland, suggested infection with the variant could be 65% more likely to result in hospitalization and 37% more likely to end in death than contracting the older version of the virus. Scientists say these findings aren’t definitive, and some studies suggested the link with higher mortality was weak or the variant may even be associated with a lower risk of dying.

Still, the evidence was sufficient for a panel of scientists advising the U.K. government to say this month that it is likely B.1.1.7 carries a greater risk both of hospitalization and death than established versions.

Surveys of patients conducted by the U.K.’s Office for National Statistics between November and January made another finding: Infection with the B.1.1.7 can result in slightly different symptoms, which may help doctors spot possible cases.

The classic symptoms of Covid-19—fever, cough and shortness of breath—were slightly more common among those with the new variant than the old. Patients reporting a loss of taste or smell were less common. And gastrointestinal complaints were more frequent in the case of the new variant.

One cold comfort for the U.K., according to public-health officials, is that the new variant is now so dominant and so transmissible that other variants of concern to epidemiologists, such as those identified in South Africa and Brazil, haven’t gained much traction. Another reason for optimism is that lab tests and some clinical studies—as well as real-world vaccination in the U.K.—suggest the variant can be neutralized by the current range of vaccines.

Dr. Philip Dormitzer, Pfizer Inc.’s chief scientific officer of viral vaccines, told U.K. lawmakers on Wednesday that the company was seeing protection against the U.K. variant in real-world data from Israel and from the U.K. “equivalent to the protection we saw in controlled trials before that variant was circulating."

Still, the variant’s rapid advance and unusual characteristics mean it remains a worry, say disease experts, especially if vaccine rollouts don’t keep pace.

“It’s a new beast," said Eric Topol, professor of molecular medicine at Scripps Research in California. He said he didn’t think it was widely appreciated that the new variant could create a new pandemic, one “driven by a tougher virus to combat."

This story has been published from a wire agency feed without modifications to the text.

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