Surge in US air travel alarming health specialists

A flood of passengers swelling Logan Airport and other US airports for the Christmas holidays is alarming public health specialists, who warn that widespread travel could result in a surge of coronavirus infections similar to outbreaks that followed Thanksgiving.

Between Friday and Monday, more than 4.1 million people flew out of US airports, a number that is above the surge in travel in the four days preceding Thanksgiving, which compounded the spread of cases now gripping the nation. Similar data indicate travel at Logan is running at a higher level than around Thanksgiving.

The increase in travel comes despite repeated entreaties from officials such as Governor Charlie Baker and Dr. Anthony Fauci, the nation’s leading infectious disease specialist, who have urged residents to limit travel as much as possible during the holidays.

“If these numbers are correct, we’re going to see another surge,” said Joshua Barocas, an infectious disease physician at Boston Medical Center and assistant professor of medicine at Boston University. “We can’t say whether this is going to be worse or better or on par [with Thanksgiving], but I see no reason why, if we’re seeing busy travel, we would see anything different.”

Barocas said he was sympathetic to Americans who, more than nine months into the pandemic, feel “lonely and desperate, and are willing to sacrifice their physical health because they are so craving the need for normalcy.” But the US travel rates are a troubling sign for the virus’s spread and the capacity of the health care system, he said.

Meanwhile, US officials said they had no immediate plans to implement new travel restrictions on flights from the United Kingdom amid mounting concerns of a worrisome mutant strain of the coronavirus that has isolated that country from much of Europe.

While dozens of countries, including Canada and several European countries, have restricted travel from the UK, Fauci, the director of the National Institute of Allergy and Infectious Diseases, said he was “not recommending” a ban on arrivals from Great Britain because it may be an “overreaction.”

In a televised interview with the BBC, Fauci did say that the United States should consider “the possibility of requiring pre-flight testing before people leave from the UK to the United States.”

Also on Tuesday, the Centers for Disease Control and Prevention acknowledged that the mutated form of the virus may already be circulating here, in part because of “ongoing travel between the United Kingdom and the United States.”

Logan currently receives 10 flights a week from London — one from British Airways each day and three a week from Virgin Atlantic. And they appear to be far from full: a little more than 500 passengers over the entire month of November, compared to 28,275 in November 2019, according to the Massachusetts Port Authority, which operates Logan.

On Tuesday, Virgin Atlantic said that as of Christmas Eve, it will require passengers from London to test negative for COVID-19 before boarding for trips to the United States. British Airways will also require tests, but only for flights into New York, after Governor Andrew Cuomo pressed for travel bans and testing requirements to contain the strain of the virus.

Massport cannot unilaterally impose a travel ban on flights from the UK, said Jennifer Mehigan, an agency spokeswoman. She noted that travelers from London are already subject to existing Massachusetts travel restrictions, which require visitors to quarantine for 14 days unless they can prove they tested negative in the prior 72 hours.

And the Federal Aviation Administration said it won’t impose restrictions on travel from the UK at this time. “This is a developing situation that we are monitoring closely,” said spokeswoman Maria Njoku.

The new strain, called B.1.1.7., is prevalent in southern England, leading to new lockdowns in London just before Christmas. That high prevalence of the mutation may indicate it is more infectious than other strains, although it has yet to be proved; public health experts say that, so far, it does not appear to cause more severe illness.

William Hanage, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health, said it could already be in the United States, which does not sequence samples of the virus as regularly as the UK or other countries where mutant strains have been found.

“Those places which have detected it are those that have good systems for this kind of surveillance,” he said. “I think, in fact, if something like that had arisen in the United States, it might be quite hard to detect, depending on which part of the country it happened in. I’m sure we can expect to hear more of it in the coming weeks.”

After being a ghost town through most of the pandemic, Logan is in its busiest period in months. Although the Transportation Security Administration does not break out numbers solely for Logan, aggregate travel data for all of New England’s six major airports showed that more than 86,500 passengers passed through security last weekend, an increase of more than 30,000 from the prior weekend and an 11 percent bump over the weekend preceding Thanksgiving. Most travel through Logan.

Baker has strongly urged Massachusetts residents to keep to their own households for Christmas and New Year’s, and on Tuesday implemented new capacity restrictions on indoor businesses and other establishments that will take effect the day after Christmas. Baker described the measures as a way to slow the spread of the virus during a period between holidays that is usually filled with social events.

“Together, the intent of these restrictions will be to pause activity and reduce mobility, so we can reduce the spread of the virus without closing our schools or our businesses,” he said at a news conference.