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In the confusing first hour or two after an Emirates Airline jet was quarantined at New York’s JFK Airport on Wednesday, there was little certainty over how many people were sick or what was ailing them. But one thing was clear: A system years in the making to spot and halt importation of dangerous illnesses to the United States was set into motion.

The system, involving federal, state, and local agencies across the U.S. at major ports of entry, is the country’s “hidden safety net,” Dr. Martin Cetron, director of the Centers for Disease Control and Prevention’s division of global migration and quarantine, told STAT.


It was activated Wednesday morning when word came in that just over 100 people on Airbus 380, inbound from Dubai, were reporting feeling ill. Some had mild symptoms; others seemed more severely ill.

Eventually most of the 106 people were deemed not to be truly ill — this was not a mass, airborne disease outbreak. Eleven people were taken to hospital but only 10 were admitted. A number tested positive for influenza and other cold-causing viruses and should be released soon, the New York City Health Department said in a statement late Thursday afternoon.

There was reason to believe it might have been otherwise.


The plane was coming from Dubai, a hub for international travel from the Middle East. The hajj, the mass annual pilgrimage to Mecca, the holiest site in the Muslim religion, had ended in late August. A large number of returning pilgrims, roughly 100, were on the plane, Cetron said.

And of course, Saudi Arabia has had more cases of MERS — Middle East respiratory syndrome — than any other country.

The disease can cause serious illness, especially in people who have pre-existing health problems. About 37 percent of the 2,253 people known to have contracted MERS have died from their infections.

MERS cases have occasionally made their way to other countries, including a recent infection diagnosed in the United Kingdom. It has turned up twice in the United States, without leading to additional cases.

In 2015, however, a South Korean businessman who was infected on a business trip to the Middle East ignited a massive outbreak when he got home — 185 cases, 36 of them fatal. Cetron, who was part of a World Health Organization team that helped South Korea respond to the outbreak, had all these things in mind when he learned of the incoming flight.

“I was particularly concerned about the possibility of MERS and other … more rare, high-consequence things where a small introductions really need to be caught very, very quickly. So that was part of the rationale for mounting a fairly aggressive response to this situation,” he said.

The fact that a rapid and aggressive response involving a number of agencies and response teams could be pulled together so quickly is thanks to work that has been underway to build this safety net since the early 1990s. That’s when a seminal report from the Institute of Medicine — now called the National Academy of Medicine — issued a clarion call of the threat emerging infectious diseases posed to the U.S.

Cetron, who has been working on quarantine and migration programs at the CDC since 1996, said a lot of work has gone into strengthening the capacity of ports of entry — land, sea, and air — to respond to the arrival of travelers who may be ill with communicable diseases that pose risks to others.

Many such incidents happen over the course of any given year, but in most cases, the CDC does not get immediate word that someone who was on a plane had a disease such as active tuberculosis or measles. In those scenarios, the agency or its partners work to track down passengers who might have been at risk.

In other cases, as on Wednesday, there is advance warning. And that gives everyone a chance to see how the plans function in action.

“The system [Wednesday] worked, but not because you can pull that off as a one-off event in the heat of the moment,” Cetron said. “It’s because there have been port preparedness plans for years that have been written and revised and iterated in partnership with state and local health departments, with other federal partners at ports, with the local EMS response system, with communications officers.”

The list of partners he named was longer, but you get the picture.

A mobile specimen collection site was set up at the airport, so testing could begin immediately. Hospitals slated to take travelers needing care had been pre-designated.

“So we had a contingency plan for ‘What if it’s 50 or 100 [sick people] versus what if it’s just 15 sick people?'” Cetron said. “All of those things are laid out in advance. And executing against a pre-planned and pre-exercised scenario really helps things go smoothly.”

Airports and other ports of entry, plus the organizations that are part of their response teams, are supposed to run practice drills. Josh Greenberg, who co-authored a 2017 report for the National Academies of Sciences, Engineering and Medicine on the issue — “Preparing Airports for Communicable Diseases on Arriving Flights” — said their study found some airports are better prepared than others.

“Larger, better resourced airports would be more likely to have practiced and stress-tested their response protocols than smaller or medium-sized airports. But even then, they don’t get opportunities to do it enough,” said Greenberg, who is director of the school of journalism and communications at Carleton University in Ottawa, Canada.

An event like Wednesday’s Emirates flight provides a good chance to really test how well the systems work, he said.

The airline industry has also been working on these issues, said Dr. Kamran Khan, an infectious diseases physician at St. Michael’s Hospital in Toronto who specializes in mapping the potential international movement of infectious diseases using airline flight data.

Events like the global spread of SARS — which rapidly fanned out from China and Hong Kong to more than two dozen countries in 2003 — have driven home the risk.

“The private sector and the public sector really have learned from some of the experiences that we’ve had in the last 10 or 15 years, and I think have become better at this,” said Khan, who is also CEO of BlueDot, a digital health company that uses big data analytics to predict possible global transmission patterns of infectious diseases.

In the JFK incident, Khan saw a system that was doing the job it was designed to do.

“The fact that this is happening within a matter of hours is encouraging,” he said. “I think the only question that will come up, and it comes up with every event is: Did we overreact or underreact? And I think threading that needle is very, very difficult when you’ve got imperfect information.”

For his part, Cetron wasn’t worrying about that question.

“Despite whatever uncertainty comes during the hysteria and the lead in, part of the job here is to bring a real systematic approach and not to be guided by the fear of the extreme,” he said. “It’s really nice to see when the systems work.”