Experts Are Skeptical That Travel Bans Can Stop the Spread of New Coronavirus Variants

It isn’t clear how widely the variants are already circulating. So the latest moves by countries to bar international travelers may again be too little, too late.

The closed port at Dover, England, on Monday as many European nations blocked arrivals from Britain because of a coronavirus variant there.Credit...Andrew Testa for The New York Times

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.

A British Airways flight arriving in New York from London on Monday.Credit...Eduardo Munoz/Reuters

Dr. Hans Kluge, the World Health Organization’s regional director for Europe, said that member states would try to come up with a coherent approach to any threat posed by the variant. At the moment, he wrote on Twitter, “limiting travel to contain spread is prudent until we have better info.”

But he noted, “no one is safe until everyone is safe.”

With growing calls for the United States to join the dozens of nations imposing bans on travel from Britain, Dr. Anthony Fauci, America’s top infectious disease expert, urged caution, saying there was a good chance the variant was already there.

“I don’t think that that kind of a draconian approach is necessary,” he said on “PBS NewsHour” on Monday night. “I think we should seriously consider the possibility of requiring testing of people before they come from the U.K. here.

Gov. Andrew M. Cuomo of New York said that British Airways, Delta Air Lines and Virgin Atlantic had agreed to require a negative coronavirus test result from passengers boarding flights from Britain to New York. In the absence of federal action, other state and local leaders called for similar measures before the peak holiday travel days.

Many countries already require a negative coronavirus test for entry, but cutting off all travel between nations is a more fraught proposition.

The European Commission, the European Union’s executive branch, urged members of the bloc to lift blanket bans on travel from Britain, but for the moment, nations seemed to prefer setting their own rules.

The situation is convulsing a travel industry already battered by the pandemic, forcing millions to change their holiday plans and injecting a fresh dose of anxiety at the end of a bleak year.

At Kennedy International Airport in New York in March. The global spread of the coronavirus has paralyzed air travel, thinning traffic at airports.Credit...Stephanie Keith for The New York Times

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.

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Answers to Your Vaccine Questions

With distribution of a coronavirus vaccine beginning in the U.S., here are answers to some questions you may be wondering about:

• • If I live in the U.S., when can I get the vaccine? While the exact order of vaccine recipients may vary by state, most will likely put medical workers and residents of long-term care facilities first. If you want to understand how this decision is getting made, this article will help.
  • When can I return to normal life after being vaccinated? Life will return to normal only when society as a whole gains enough protection against the coronavirus. Once countries authorize a vaccine, they’ll only be able to vaccinate a few percent of their citizens at most in the first couple months. The unvaccinated majority will still remain vulnerable to getting infected. A growing number of coronavirus vaccines are showing robust protection against becoming sick. But it’s also possible for people to spread the virus without even knowing they’re infected because they experience only mild symptoms or none at all. Scientists don’t yet know if the vaccines also block the transmission of the coronavirus. So for the time being, even vaccinated people will need to wear masks, avoid indoor crowds, and so on. Once enough people get vaccinated, it will become very difficult for the coronavirus to find vulnerable people to infect. Depending on how quickly we as a society achieve that goal, life might start approaching something like normal by the fall 2021.
  • If I’ve been vaccinated, do I still need to wear a mask? Yes, but not forever. Here’s why. The coronavirus vaccines are injected deep into the muscles and stimulate the immune system to produce antibodies. This appears to be enough protection to keep the vaccinated person from getting ill. But what’s not clear is whether it’s possible for the virus to bloom in the nose — and be sneezed or breathed out to infect others — even as antibodies elsewhere in the body have mobilized to prevent the vaccinated person from getting sick. The vaccine clinical trials were designed to determine whether vaccinated people are protected from illness — not to find out whether they could still spread the coronavirus. Based on studies of flu vaccine and even patients infected with Covid-19, researchers have reason to be hopeful that vaccinated people won’t spread the virus, but more research is needed. In the meantime, everyone — even vaccinated people — will need to think of themselves as possible silent spreaders and keep wearing a mask. Read more here.
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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.

Oxford Street, one of London’s main shopping streets, last week.Credit...Andrew Testa for The New York Times

That means that by the time Prime Minister Boris Johnson addressed the nation on Saturday night to announce severe new lockdown measures for millions of people in and around London, the variant had been spreading for months.

Officials in France and Germany acknowledged on Tuesday that the variant might already be circulating in their countries. The European Centre for Disease Prevention and Control said a few cases with the new variant had been detected in Denmark, Iceland and the Netherlands. And health officials in Australia and Italy have reported cases in travelers from Britain.

Those who support the travel bans said they could play a role in keeping cases of new variants lower.

“Numbers matter,” Emma Hodcroft, a researcher at the University of Bern in Switzerland, wrote on Twitter. “The number of people with the new variant in continental Europe is likely still small: with testing, tracing, identification and restrictions, we might be able to prevent them from passing the virus on.”

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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