Medical teams at New York's JFK airport, armed with Ebola questionnaires and temperature guns, began screening travelers from three West African countries on Saturday, as U.S. health authorities stepped up efforts to stop the spread of the virus.
John F. Kennedy Airport is the first of five U.S. airports to start enhanced screening of U.S.-bound travelers from Guinea, Liberia and Sierra Leone, where most of the outbreak's more than 4,000 deaths have occurred.
Nearly all of passengers traveling to the United States from those countries arrive at JFK, Newark Liberty, Washington Dulles, Chicago O'Hare and Hartsfield-Jackson Atlanta. The new procedures will begin at the other four airports on Thursday.
Before it even began, some critics questioned whether the screenings would be effective in stopping infected travelers from entering the country.
The Centers for Disease Control and Prevention said the airport screening is just one aspect of an overall strategy to fight the spread of Ebola.
"No matter how many of these procedures are put into place, we can't get the risk to zero," said Martin Cetron, director of the Division of Global Migration and Quarantine at the CDC.
"This new entry-screening procedure is just one part of a multi-layered approach," he told a news conference at JFK on Saturday morning.
Other measures include screening of passengers upon boarding a flight and the protocol to manage an illness when it occurs during a journey, he said.
JFK is the entry point for nearly half of the roughly 150 travelers who arrive daily in the United States from the three West African countries, and those passengers amount to about one-tenth of 1 percent of all international daily arrivals at the airport, the CDC said.
The screenings are being conducted by the Department of Homeland Security's Customs and Border Protection (CBP), under CDC direction. Given there are no direct flights from the affected countries, CBP staff will identify passengers who have flown from there by looking at information about their trip as well as by checking passports, said R. Gil Kerlikowske, the CBP commissioner.
Using FDA-approved infrared temperature guns, staffers will check for elevated temperatures among passengers whose journeys began or included a stop in one of the three African countries.
As a temporary measure, the CBP has authorized U.S. Coast Guard personnel to take temperatures, but the CBP will contract "professional medical staff" in the future, Kerlikowske said.
Screeners will also assess passengers for signs of potential illness and ask them questions about their health and whether they may have come into contact with an Ebola patient.
For those with a fever or other symptoms or possible exposure to Ebola, the CDC will decide what steps to take next. Health authorities may decide to take a person to a hospital for evaluation, testing and treatment, or to quarantine or isolate the patient under federal law, according to the CDC.
Even before the screening began, critics questioned it.
U.S. health authorities have never before used fever monitoring to screen travelers, said Lawrence Gostin, who teaches global health law at Georgetown Law School, and such monitoring didn't work well when used in Canada and Asia during the SARS outbreak in 2002.
Fever-monitoring "had virtually no effectiveness," he said. Taking over-the-counter medication during the flight can easily help travelers bring down a fever to evade detection, he said.
Passengers also could lie on questionnaires, said Dr. David Mabey, a professor at the London School of Hygiene and Tropical Medicine. "People may not fill them in very truthfully. They don't want to be delayed for hours," Mabey said.
Passengers are already screened when they depart from the three West African countries. In the two months since those screenings began, only 77 of the 36,000 screened travelers were denied boarding, the CDC said. Many of them were diagnosed later with malaria, and none with Ebola.
Thomas Eric Duncan, who died of Ebola in Dallas this week, was able to fly to the United States from Liberia because he didn't have a fever when screened at the airport in the capital, Monrovia.
Duncan filled out a questionnaire saying he had not been in contact with anyone infected with Ebola. Liberian officials have said Duncan lied on the questionnaire and had been in contact with a pregnant woman who later died. However, a friend of his family has said Duncan did not know the woman had Ebola.
Both Mabey and Gostin said it was unlikely that a person who passed the temperature screening at departure time would develop a high fever during the plane ride to the United States
But Dr. Jeffrey Griffiths, who teaches about infectious disease at Tufts University School of Medicine, said the U.S. screenings "will incrementally pick up some people" and are a valuable tool to raise awareness about early detection and treatment of the illness.