Airport screenings of travelers from West Africa haven't turned up anyone with Ebola, health officials announced Tuesday.
U.S. officials screened nearly 2,000 travelers for Ebola symptoms over 31 days in October and November, according to a report Tuesday from the Centers for Disease Control and Prevention.
Only seven travelers with symptoms were referred to the CDC for medical exams, and none had the disease, the report says.
Although two travelers from West Africa were later diagnosed with Ebola -- an American doctor and a Liberian national -- neither had symptoms in the air or in airports.
The diagnosis in September of the first Ebola patient in the USA, Thomas Eric Duncan, led to widespread calls for travel bans from affected countries. While President Obama rejected an outright ban, the CDC announced in October that it would work with U.S. Customs and Border Protection to screen travelers from Ebola-affected countries in West Africa, funneling those air passengers through five major airports.
The CDC also has worked with the World Health Organization and officials in Liberia, Sierra Leone and Guinea, the five hardest-hit countries, to screen passengers before they exit those countries.
About 80,000 air travelers have flown out of the three countries since August, about 12,000 of them bound for the USA, according to the CDC report. The three countries prevented anyone with possible Ebola symptoms, such as a fever, from boarding a plane. None of the travelers prevented from boarding turned out to have Ebola, the CDC says.
No one who was permitted to travel had Ebola symptoms in the air or in the airport. Two travelers – Duncan and New York physician Craig Spencer – developed symptoms days after arriving in the USA.
U.S. officials screened 1,993 travelers from West Africa from Oct. 11 through Nov. 10, the CDC says. Seven who had symptoms were referred to the CDC for additional medical exams. None tested positive for Ebola. About 3% of the 1,993 travelers had worked in a health care facility or lab in an Ebola-affected country. According to flight data, fewer than 0.06% of all airplane passengers arriving in the USA came from those three countries.
On Nov. 17, officials also began screening passengers arriving from Mali, the latest country to experience an Ebola outbreak.
On Friday, the CDC reported that doctors and other health workers made 650 inquiries about possible Ebola cases from July 9 through Nov. 15. Eighteen percent of those cases had possible symptoms of Ebola and a risk factor for infection, such as recent travel to West Africa. Four cases were positive: Spencer, Duncan and two of Duncan's nurses, Amber Vinson and Nina Pham.
But 75% of the inquiries involved people who had zero risk of Ebola, because they hadn't been to West Africa and hadn't had contact with an Ebola patient, the CDC says.
About 17,800 people have been diagnosed with Ebola in Sierra Leone, Guinea and Liberia, according to the WHO. Sierra Leone, with 7,798 cases, has overtaken Liberia as the country that has had the most people infected.
Even if airport screenings didn't turn up any Ebola patients, "it was a "necessary step in order to provide some public reassurance in the days following the arrival of Mr. Duncan in Dallas," says Peter Hotez, dean of the National School of Tropical Medicine in Houston. "There was not a lot of precedent to go on."
Infectious disease expert Robert Murphy sees airport screening as "overkill" and "a big waste of time." Health professionals know how to monitor themselves, says Murphy, the director of the Center for Global Health at Northwestern University Feinberg School of Medicine.
Murphy, who also works as the program director at a lab in Mali that does Ebola testing, was screened last month at Chicago's O'Hare International Airport after changing planes in France.
French officials took his temperature, gave him some written information and told him that, if he developed a temperature, not to go to a hospital or doctor's office. Instead, he was told to call an Ebola hotline so that health workers could pick him up.
Screening was far more complicated in Chicago, Murphy says.
"I waited in a crowded immigration holding pen with hundreds of other people," Murphy says. "When I got to the immigration officer, he told me to put on a mask, even though I had no symptoms and had just been standing for an hour or so with several hundred people."
When officials learned that Murphy worked in a lab – but didn't have contact with patients – "they returned wearing masks and face shields. They tried asking more questions, but you can't really understand anyone who is talking with a mask and shield on.
Finally, he said, someone wearing just a mask "came over and took my temperature again and asked more questions."
Two people from Chicago's public health department then met with Murphy and gave him a packet of information and a thermometer. A CDC officer gave him a card with contact information and a traveler identification number. Murphy had to sign an agreement to monitor his temperature and report in twice a day.
"If I didn't follow these rules," he says, "I would be charged with a misdemeanor and then put into mandatory quarantine."
Officials told Murphy he would be allowed to see a dentist for a cracked tooth, but "had to talk to the public health monitor before I went."