Why Experts Think Travel Bans Won’t Stop Coronavirus Variant Spread


LONDON — As nation after nation rushed this week to close their borders with Britain, the moves brought back memories of the way the world reacted after the coronavirus first emerged broadly in the spring. Most of those initial travel prohibitions came too late, put in place after the virus had already seeded itself in communities far and wide.

This time, with countries trying to stop the spread of a new, possibly more contagious coronavirus variant identified by Britain, it may also be too late. It is not known how widely the variant is already circulating, experts say, and the bans threaten to cause more economic and emotional hardship as the toll wrought by the virus continues to grow.

“It is idiotic” was the blunt assessment of Dr. Peter Kremsner, the director of Tübingen University Hospital in Germany. “If this mutant was only on the island, only then does it make sense to close the borders to England, Scotland and Wales. But if it has spread, then we have to combat the new mutant everywhere.”

He noted that the scientific understanding of the mutation was limited, and its dangers unclear, and described as naïve the notion that the variant was not already spreading widely outside Britain.

Also, Britain has some of the most sophisticated genomic surveillance efforts in the world, which allowed scientists there to discover the variant when it might have gone unnoticed elsewhere, experts said.

At the same time, a separate variant of the virus is causing concern as it spreads in South Africa. At least five nations — Germany, Israel, Saudi Arabia, Switzerland and Turkey — have barred travelers coming from South Africa.

Sweden blocked travel from Denmark after reports that the British variant had been detected there. And Saudi Arabia went even further, suspending all international air travel into the kingdom for at least a week.

The South Africa variant became the subject of intense scientific research after doctors there found that people infected with it carry a heightened viral load — a higher concentration of the virus in their upper respiratory tract. In many viral diseases, this is associated with more severe symptoms.

Because it is not known how widely the two variants are spreading, it is impossible to assess what effects the attempts to isolate Britain and South Africa will have on containing them.

With its sophisticated genomic surveillance efforts, Britain has sequenced about 150,000 coronavirus genomes in an effort to identify mutations. That’s about half of the world’s genomic data about the virus, said Sharon Peacock, the director of the Covid-19 Genomics U.K. Consortium and a professor of microbiology at the University of Cambridge.

“If you’re going to find something anywhere, you’re going to find it probably here first,” Professor Peacock said. “If this occurs in places that don’t have any sequencing, you’re not going to find it at all,” she added, unless they carried out other tests that have proved useful in identifying the variant.

In Wales, a country of three million people, geneticists have sequenced more coronavirus genomes in the last week than scientists have examined during the entire pandemic in France, a country of 67 million, said Thomas Connor, a professor who specializes in pathogen variation at Cardiff University.

“It is probable that similar variants are popping up around the world,” he said. “And there are variants that are likely to be popping up in other places which are spreading locally and which would be completely unregarded because there’s no sequencing in place.”

British officials have said that the first case of the variant now spreading widely in the country was detected in Kent, in southeastern England, on Sept. 20. By November, around a quarter of cases in London — an international hub of commerce — involved the new variant. Just a few weeks later, the variant was estimated to be responsible for nearly two-thirds of cases in Greater London.

If the variant does prove to be significantly more contagious than others in circulation and becomes more widespread, it could complicate global vaccination efforts.



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