Airports Have No Way to Screen for Ebola

Traditional thermal screenings at international airports won’t be much help.

National Journal
Patrick Tucker, Defense One
Aug. 1, 2014, 1:25 p.m.

The Ni­geri­an gov­ern­ment an­nounced Thursday that it had star­ted screen­ing pas­sen­gers at in­ter­na­tion­al air­ports for signs of Ebola after a pas­sen­ger showed up in La­gos suf­fer­ing from the ill­ness, which kills up to 90 per­cent of the people in­fec­ted with it. Treat­ment op­tions are ex­tremely lim­ited. Ni­geri­an air­port au­thor­it­ies will be check­ing pas­sen­gers who just ar­rived from Si­erra Le­one, cur­rently un­der a state of emer­gency, and they’ll be look­ing for fever, since an el­ev­ated tem­per­at­ure is con­sidered a sign of Ebola. If the pas­sen­ger is present­ing with high­er than nor­mal tem­per­at­ures, screen­ers would sub­ject the pas­sen­ger to a blood test.

Ebola is mov­ing in­to more coun­tries across Africa, but not as quickly as is alarm. South Africa an­nounced Thursday that it was in the pro­cess of out­fit­ting air­ports with thermal scan­ners to de­tect fe­ver­ish pas­sen­gers. In many ways, it’s a re­peat of 2009, when air­ports around the world brought in thermal scan­ners to look for pas­sen­gers who were present­ing with fever and sus­pec­ted bird flu.

Ebola has ar­rived in the United States in the form of a vic­tim who is here for treat­ment un­der care­ful ob­ser­va­tion. The CDC con­firmed that at least one Ebola vic­tim is headed out of Africa to the United States to be treated in At­lanta. The pa­tient will be flown in a spe­cial N173PA jet. “The plane will be ar­riv­ing at Dob­bins Air­base in Geor­gia, and from there the pa­tients will be trans­por­ted on to whatever the med­ic­al fa­cil­ity they’re go­ing to be treated in. But that’s the lim­it of our in­volve­ment,” Pentagon spokes­man Rear Adm. John Kirby said Fri­day. Au­thor­it­ies didn’t dis­close the pa­tient’s name but re­search­ers know of at least one Amer­ic­an doc­tor, Kent Brantly, of Fort Worth, Texas, who was work­ing to staunch the out­break in Liber­ia and who picked up the ill­ness.

“All I am aware of, in terms of­it­ary in­volve­ment, is that we have a couple of Army re­search­ers down in Africa, in Liber­ia, right now who have been for some time work­ing on this par­tic­u­lar vir­us,” Kirby said.

The good news is that neither the White House nor the epi­demi­olo­gists that spoke to De­fense One ex­pects Ebola to have nearly as deadly an ef­fect in the it is hav­ing in Africa, where more than 729 people have already died.

The bad news is that thermal screen­ings of the in­ter­na­tion­al fly­ing pop­u­la­tion at air­ports are not likely to yield much by way of im­proved safety.

Here’s why: Fever can be a sign of a lot of dif­fer­ent ill­nesses, not just Ebola. And thermal scan­ning proved to be a poor meth­od of catch­ing bird-flu car­ri­ers in 2009. So present­ing with an el­ev­ated tem­per­at­ure at an air­port check­point does not in­dic­ate clearly enough that the fevered per­son is car­ry­ing the deadly vir­us. More im­port­antly, the in­cub­a­tion peri­od for Ebola is two days. As many as 20 days can pass be­fore symp­toms show up. That means that an in­di­vidu­al could be car­ry­ing the vir­us for two weeks or longer and not even know it, much less have it show up via thermal scan. So what good are these scan­ners?

“I think that thermal screen­ers help people feel safe,” Dr. Noreen Hynes, with the Johns Hop­kins Bloomberg School of Pub­lic Health, told De­fense One.

The second meth­od that the Ni­geri­an gov­ern­ment is us­ing to de­tect the pres­ence of Ebola in — pos­sibly — fe­ver­ish pas­sen­gers is a blood test. The pres­ence of an­ti­bod­ies in the blood is a much more con­clus­ive sign of the deadly vir­us. Un­for­tu­nately, sub­ject­ing hun­dreds or pos­sibly thou­sands of pas­sen­gers to a blood test for Ebola would be prac­tic­ally im­possible in a ma­jor air­port without slow­ing in­ter­na­tion­al air travel to a crawl. The cur­rent meth­od for per­form­ing one of these tests, also called a poly­merase chain-re­ac­tion test, can take eight hours or longer, re­quires res­ults to be sent to a lab, and is pro­hib­it­ively ex­pens­ive in many cases.

Ex­perts agreed that a test able to re­veal the pres­ence of Ebola on loc­a­tion at an air­port check­point — and do so in a re­l­at­ively short amount of time — would greatly im­prove au­thor­it­ies’ abil­ity to stop the vir­us from cross­ing in­ter­na­tion­al bor­ders. One per­son work­ing on that is Dou­glass Simpson, CEO of Cor­genix, which in June re­ceived a $3 mil­lion Na­tion­al In­stitue of Health grant to de­vel­op a point-of-care test for Ebola. Air­port screen­ers would use it to spot the vir­us in a fe­ver­ish pas­sen­ger in just 10 minutes. “Our job is to as quickly as pos­sible ad­vance those tests and make them avail­able in those zones,” Simpson said.

It’s ex­actly the sort of thing that could provide much more con­clus­ive evid­ence of a pas­sen­ger with Ebola. But it won’t be in the hands of air­port screen­ers for years. “We’re sev­er­al years from get­ting it com­pleted,” says Simpson, who hopes that Cor­genix will have a rap­id test for Ebola by 2016.

What do we have to pro­tect us today? The same thing we have to pro­tect us from dan­ger­ous ter­ror­ist mas­ter­minds: back­ground screen­ing.

Be­cause the pop­u­la­tion of people who have this ill­ness is re­l­at­ively small and we have some idea of the areas that have been ex­posed, Ebola is an ex­ample of a threat that could be bet­ter man­aged at air­ports by pick­ing out those people who were most likely to have en­countered the dis­ease based on where they had been.

“The nature of Ebola makes it sim­il­ar to, but also dif­fer­ent than tra­di­tion­al avi­ation threats. Avi­ation se­cur­ity pro­tects against the flight on hand, while screen­ing for Ebola has a longer foot­print to dis­play and pro­tect,” Shel­don H. Jac­ob­son, a pro­fess­or of com­puter sci­ence at the Uni­versity of Illinois, told De­fense One.

It’s a sub­ject that he knows a lot about. In 2012, his pa­per Ad­dress­ing Pas­sen­ger Risk Un­cer­tainty for Avi­ation Se­cur­ity Screen­ing ef­fect­ively showed that too much ran­dom screen­ing at air­ports was mak­ing TSA and bor­der agents less ef­fect­ive at their jobs. The guards were scan­ning, pat­ting, and fo­cus­ing on people who posed no real threat, ef­fect­ively de­sens­it­iz­ing them to people who may have had more in­tent and ca­pa­city to com­mit harm. “A nat­ur­al tend­ency, when lim­ited in­form­a­tion is avail­able about from where the next threat will come, is to over­es­tim­ate the over­all risk in the sys­tem” Jac­ob­son said in a state­ment around the time of the pa­per’s re­lease. “This ac­tu­ally makes the sys­tem less se­cure by over-al­loc­at­ing se­cur­ity re­sources to those in the sys­tem that are low on the risk scale re­l­at­ive to oth­ers in the sys­tem.”

Pre-screen­ing pas­sen­gers for Ebola on the basis of where the pas­sen­ger has been and the like­li­hood of com­ing in­to con­tact with the dis­ease is prob­ably a more ef­fect­ive means to catch it than is try­ing to take the tem­per­at­ure of thou­sands of people with a cam­era, ac­cord­ing to Jac­ob­son. “Pre­screen­ing would be prudent, and reas­on­able, based on the in­form­a­tion avail­able. Pub­lic-health per­son­nel would need to de­vel­op ap­pro­pri­ate cri­ter­ia that yield good res­ults and also lim­it false pos­it­ives. In es­sence, pre­screen­ing, if done ap­pro­pri­ately, can work in any type of screen­ing mech­an­ism,” he wrote to De­fense One in an email.

Ebola is passed through flu­ids such as blood and so health care work­ers treat­ing in­fec­ted pop­u­la­tions, and do­ing so in less than ideal set­tings like clin­ics in Si­erra Le­one, are the most vul­ner­able. Hynes says that’s one reas­on the typ­ic­al Amer­ic­an is at much less risk.

(Of course, in most cine­mat­ic de­pic­tions of a zom­bie out­break, zom­bie­ism is also passed via flu­ids, and, as in the case of Ebola, car­ri­ers are am­bu­lat­ory for long peri­ods of time. Pub­lished mod­el­ing has shown that a zom­bie out­break would spread across a ma­jor city like Lo­gos in a peri­od of four days. But zom­bies­im, as de­pic­ted fic­tion­ally, is also ac­com­pan­ied by psychot­ic can­ni­bal­ism, which serves as an ac­cel­er­ant to spread. Ebola is ac­com­pan­ied by mal­aise, which has the op­pos­ite ef­fect.)

Hynes ac­know­ledges that while the U.S. won’t be­come like Si­erra Le­one, more people will be get­ting the ill­ness in the months ahead. “Right now the tra­ject­ory is still in the up­ward mode,” she said.

The is­sue of Ebola slip­ping in­to the United States is part of the broad­er, hot­ter dis­cus­sion on bor­der con­trol, which en­tails everything from keep­ing po­ten­tial ter­ror­ists out of the coun­try to de­tect­ing nuc­le­ar weapons, to hous­ing, pro­cessing and caring for the some 57,000 im­mig­rant chil­dren who have crossed in­to the coun­try il­leg­ally since Oct. 1. These are all fun­da­ment­ally dif­fer­ent chal­lenges. Some pose mor­tal threats, oth­ers do not. But from a polit­ic­al per­spect­ive they share the bor­der in com­mon. That can lead to politi­cians who want to treat every in­cur­sion over the bor­der with equal alarm, as Rep Michelle Bach­man, R-Minn, ef­fect­ively did the oth­er day, claim­ing the coun­try’s south­ern bor­der was an open in­vit­a­tion “not only people with po­ten­tially ter­ror­ist activ­it­ies, but also very dan­ger­ous weapons are go­ing to cross our bor­der in ad­di­tion to very dan­ger­ous drugs, and also life-threat­en­ing dis­eases, po­ten­tially in­clud­ing Ebola and oth­er dis­eases like that.”

On Thursday, a sub­com­mit­tee of the House Com­mit­tee on Sci­ence, Space, and Tech­no­logy tackled the is­sue in a spe­cial hear­ing on the tech­no­logy needed to se­cure Amer­ica’s bor­der. The hear­ing did not touch on Ebola, but the pan­el­ists were largely in agree­ment on one key point: The Home­land Se­cur­ity De­part­ment has no ef­fect­ive means for eval­u­at­ing the de­ploy­ment of bor­der tech­no­logy.

While point-of-care tests for Ebola won’t be de­ploy­able for at least two years, bio­met­ric fa­cial-re­cog­ni­tion tech­no­logy and oth­er se­cur­ity screen­ing tech­no­lo­gies are far more ad­vanced, but they have yet to be fully im­ple­men­ted. “The tech­no­lo­gies are good and ma­ture. I think one of the areas where DHS struggles is tooth to tail. Where do you have people to back up and in­teg­rate with tech­no­logy to make the best ef­fect­ive use of it. DHS ac­quis­i­tion pro­cesses are matur­ing “¦ but are not per­fect,” Jack Ri­ley, the dir­ect­or of the RAND Na­tion­al De­fense Re­search In­sti­tute, test­i­fied.

“We worked on an eval­u­ation for a tech­no­logy for bio­met­ric iden­ti­fic­a­tion at air­ports. The tech­no­logy was quit ready. It was off the shelf. It was ef­fect­ive. The prob­lem was it couldn’t be in­teg­rated in­to the hu­man sys­tems,” test­i­fied Joseph D. Ey­e­r­man, the dir­ect­or for re­search and man­age­ment at the In­sti­tute for Home­land Se­cur­ity Solu­tions at Duke Uni­versity, mean­ing that hu­man air­port screen­ers couldn’t use the data from the fa­cial-re­cog­ni­tion sys­tems, for a vari­ety of reas­ons.

How to make sure screen­ing tech­no­logy is im­ple­men­ted at air­ports and oth­er check­point is no simple mat­ter, but it could be­come one. Ri­ley sug­ges­ted that bor­der czar could help make sure that the tech­no­logy to catch nuc­le­ar weapons, and per­haps Ebola, isn’t mis­spent screen­ing im­mig­rant chil­dren who are very un­likely to be har­bor­ing either. “We need a single point of ac­count­ab­il­ity on the bor­der so that we can be­gin to un­der­stand some of these large tradeoffs,” Ri­ley toldDe­fense One.

When asked by com­mit­tee Chair­man Lamar Smith, R-Texas, how they would rate the Home­land Se­cur­ity De­part­ment’s use of bor­der tech­no­logy, the wit­nesses answered uni­formly: in­com­plete.

Des­pite cen­tur­ies of pro­gress, in many ways our abil­ity to catch dis­ease at a bor­der hasn’t changed much since 1374 when the Black Death was lay­ing waste to pop­u­la­tions of Europe. It was at this time that the doge of Venice put in place a pro­tocol to at­tempt to ar­rest the dis­ease in port. He cre­ated three so-called guard­i­ans of health. They were health screen­ers and their job was to board ships in port and in­spect crew for in­flamed lymph nodes. If symp­toms were found, or sus­pec­ted aboard the crew, the guard­i­an would or­der the ship away from port for a peri­od of 40 days.

Not enough has changed. The cur­rent Ebola out­break is un­likely to claim the lives of hun­dreds of Amer­ic­ans, and will likely run its course be­fore sum­mer of next year. The ques­tion of how to catch dis­eases at the bor­der is not go­ing to go away. But be­cause of our in­nate tend­ency to “over­es­tim­ate the over­all risk in the sys­tem,” we will be in­clined to treat every in­cur­sion over the bor­der as an equal threat. The next time a ma­jor out­break hits, tech­no­logy to de­tect it will be more ad­vanced. Our abil­ity to im­ple­ment that tech­no­logy may not be.