Homeland Security

The Law and Policy of Ebola Interdiction

By Paul Rosenzweig
Thursday, October 9, 2014, 7:00 AM

A few days ago President Obama announced his intention to do greater screening of passengers arriving in the United States, as a way of interdicting the spread of the Ebola virus. According to the Washington Post, the new procedures will include “entry” screening – that is screening upon arrival in the United States – layered on top of the already existing “exit” screening that is being conducted at airports in West Africa. “The new screening possibilities being considered by the administration include taking the temperature of travelers from affected countries upon their arrival at major U.S. airports and more-closely tracking travel histories for international travelers arriving in the United States.” According to an NPR story today, the new screening will happen at the top 5 airports in the US (including Dulles) and will at least in part also involve CBP officers “looking at patients for signs of distress.”   [Traffic to the US from West Africa typically transits Europe. Given the current African focus of Ebola the other 4 airports being covered are also European-focused: JFK, Atlanta, O’Hare and Newark. Note that this still leaves large transit hubs like Miami and Dallas uncovered for now.]

It is useful, as this plan moves forward, to consider both some of the legal issues involved in such screening and some of the practical/policy considerations that are likely driving the discussion. Herewith a short synopsis [with the caveat that my own experience is exclusively in the DHS/homeland security law space – there are applicable public health laws, with which I’m generally familiar, but I lack expertise and may misstate slightly – corrections welcome]:

Legal Authority

In dealing with a pandemic from overseas, HHS has, pursuant to the Public Health Service Act, 42 U.S.C. 201 et seq., statutory and regulatory responsibility for preventing the introduction, transmission, and spread of communicable disease from foreign countries into the United States. Applicable HHS regulations are found in 42 C.F.R. Parts 34 and 71. These responsibilities are delegated to the Centers for Disease Control and Prevention (CDC), National Center for Infectious Diseases, Division of Quarantine.

HHS also has primary statutory authority, pursuant to 42 U.S.C. 269, to designate and post medical officers overseas, to require that conveyances produce a clean bill of health before being permitted to depart from a foreign port for the United States, and to prescribe additional regulations for preventing the introduction of communicable disease into the United States.

Under the Aviation and Transportation Security Act, the Transportation Security Administration (TSA) is “responsible for security in all modes of transportation. . . .” 49 U.S.C. 114(d). Specific authorities to carry out this responsibility include “coordinating countermeasures with appropriate departments, agencies, and instrumentalities of the United States,” 49 U.S.C. 114(f)(4), and issuing and revising security-related regulations and requirements, “including issuing regulations and security directives without notice or comment . . . as are necessary to carry out TSA functions.” 49 U.S.C. 114(l)(1) and (2). Accordingly, (assuming we characterize disease as a security risk), TSA may assist in preventing the introduction or spread of quarantinable disease through the transportation system. Finally, pursuant to 42 U.S.C. 268(b), “[i]t shall be the duty of the customs officers and of Coast Guard officers to aid in the enforcement of quarantine rules and regulations.” Personnel of both CBP and U.S. Immigration and Customs Enforcement (ICE) exercise customs authorities and therefore qualify as “customs officers” under this provision, as do most Coast Guard officers under 19 U.S.C. 1401.

In practice, for arriving passengers at American airports, this means that DHS will work with HHS to ensure that aliens carrying a quarantinable disease such as pandemic influenza are found inadmissible to the United States – and therefore returned to their point of origin on the next flight. DHS has general authority under Section 212(a)(1) of the Immigration and Nationality Act (INA) (8 U.S.C. 1182(a)(1)) to find inadmissible any alien “who is determined (in accordance with the regulations prescribed by the Secretary of Health and Human Services) to have a communicable disease of public health significance.” One gap is that Ebola is not (at least as I understand it) on the current regulatory prescribed list – though I imagine that is changing rapidly.

A more difficult issue is with regard to U.S. citizens carrying a quarantinable disease. There is no legal authority to turn back a U.S. citizen determined to have such a disease. HHS regulations, however, do provide for the isolation, quarantine, or surveillance of a person, regardless of citizenship, suspected of having a quarantinable disease. Note that this authority is limited to the CDC, but one suspects that were such a person to arrive at a port of entry where there are no officials from CDC, the courts would uphold a reasonable temporary detention of possibly ill individuals by CBP officers until a health determination could be made.


Buried in this challenge are dozens of difficult policy/practicality/implementation questions and issues. One could (and, indeed, I’m sure someone at DHS and/or CDS is busy as we speak) write reams on the various topics. Here are just a few to highlight as matters that must be going through the minds of decision-makers:

  • How reliable is exit screening in origin countries? To date roughly 100 boarding passengers have reportedly been denied the right to leave West Africa. We have no real data on how many more might have been permitted to travel but should not have (as with the Texas victim who passed away this week). In the absence of pre-negotiated screening agreements with foreign nations and training of their public health staff we are, essentially relying on their assurances.
  • How effective will entry screening be? For one thing, one of the reasons that the initial deployment is limited to 5 major airports is that there aren’t that many trained CDC officers available to conduct screening.  Though CDC has more than 6,500 officers, they are shared and spread among nearly two dozen agencies – and not all have the relevant medical experience. Pre-crisis, their work load at airports is generally “one-off” cases, not systematic screening of all arriving passengers. More importantly, do we have any models or experience with assessing how successful a combination of observation, questioning and testing will be. We will, I think, be fortunate, if the trained screening identifies 90% of those who should be identified. Lower success rates are highly likely.
  • Can CBP be a force multiplier? CBP officers are now screening arrivals for “obvious signs” of Ebola. I don’t know what these are, myself. Even with training, however, well-meaning CBP officers are not trained health professionals. They can follow checklists, but they will inevitably make mistakes in judgment. Whatever their effectiveness, we know it will be less than that of their CDC colleagues.
  • Given these efficacy concerns, can we improve our success in screening by funneling air traffic to major airports with a robust CDC presence? It would seem so – but only at some significant economic cost. There are, right now, as I said, no direct flights from West Africa to the US. Thus, almost all arrivals from infected areas have transited Europe.   The US-Europe air bridge is the largest single component of our air traffic – thinking about re-routing those flights (and therefore, say, prohibiting flights from Amsterdam to DFW) is pretty disrupting.
  • Can we do more than screening by limiting or conditioning travel from West Africa? Maybe. For non-resident aliens traveling from affected areas, options could include a series of escalating measures from voluntary travel restrictions to health certification requirements at exit ports, to mandatory travel restrictions and exclusion from the United States. For U.S. citizens/legal permanent residents, however, we can’t eliminate their right to return. For them we might require predicate screening, quarantine, treatment, and other prophylaxis measures to reduce the risk of transmission of to the domestic United States population – but we cannot reject them altogether.
  • Can we even identify all the passengers arriving from West Africa? Probably not. If a passenger purchases a through ticket (from, say Liberia to Paris to JFK) the entire itinerary is visible to CBP in its automated arrival system. If, however, the tickets were purchased separately, or there was a break in travel, then only the Paris to JFK leg will appear. Only with much deeper and more detailed information on arriving passengers (information to which the US is not generally entitled under existing rules governing flights from Europe) could the broader travel pattern be discovered. I’ve seen estimates that 150 passengers arrive each day in the US, having recently been in West Africa. My guess is that something like ¼ are on itineraries that don’t reflect the country of origin. How likely they are to disclose that origin in response to questioning is anybody’s guess – but if I were trying to get to the US for treatment, I wouldn’t risk being turned back.
  • What do we do with flights carrying an infected individual? Imagine that a plane arrives and an Ebola-infected passenger is found to be on board. What do we do with all the =other= people on the plane. Do we impose mandatory quarantine on them all at the airport? Do we allow them to go home and assume they will abide by a home quarantine order? Do we apply these rules to all the passengers or only those seated within some distance (3 rows? 5?) of the infected individual?
  • Can we even implement a mandatory quarantine at an airport if we wanted to? Most airports have room for a few (less than a dozen) people to be isolated. They aren’t hospital wards. Some of the challenges of mandatory isolation and quarantine of travelers at this stage would include the following: limited HHS presence at U.S. international airports; limited number of quarantine stations; training requirements for DHS and other airport personnel; and the logistical support required for quarantined travelers (e.g., food, shelter, medical care, communications, etc.).
  • What are the costs? The costs of screening are potentially large, but essentially unmeasurable. Initially they will be limited to the costs of delay at airports. Consider it this way – in 2011 (the last year for which the Department of Commerce has statistics) nearly 72 million passengers arrived in the US from other countries (excluding Canada). If the additional screening we are contemplating adds only 10 seconds to each interaction between CBP and the arriving public, the law of large number quickly overwhelms you. A good rule of thumb is that 10 more seconds/person is an extra hour of screening for each large arriving airliner. Either things slow down, or we incur a lot of overtime for CBP officers to handle the delay in throughput. Either way, travel disruption can grow to become a significant factor. Of course, to the extent we wind up having large quarantine costs or hospital-based treatment costs on the public health side, those will probably outweigh travel delay costs – but I know much less about those and can’t really even begin to estimate them.
  • Will cargo be effected? It probably shouldn’t be (given my limited knowledge of Ebola’s transmission methods, cargo does not seem to be a vector of contamination).   But if it is, then the costs of additional screening just increased substantially. Granted, we probably get little cargo from West Africa – but, as I said, most of it transits Europe. And if European cargo is generally subject to more scrutiny, now we are talking about significant business disruption. The domestic macroeconomic impact is potentially an economy-breaker – and the ripple effect globally would also be notable.
  • Here’s another chestnut: What about diplomats from West Africa? Can they be interdicted? One suspects their governments would object.
  • Don’t even get me started on the land border …. The difficulty of screening there is immensely greater than at airports.
  • Is the game even worth the candle? Back when I was at DHS some public health professionals did models of the effectiveness of screening and interdiction on the spread of pandemic influenza – like avian flu. Now, granted, there are =huge= differences between Ebola and avian flu. Different diseases; different infectious pathways etc. I have no idea if the modelling results are even relevant within an order of magnitude. Still, for the flu the results back then were sobering.   If I recall correctly (and I may not be exact but on this I =am= in the right order of magnitude), screening that was 90% effective (which would probably be a huge success in most contexts) delayed arrival of the pandemic in the US by 1-2 weeks. Nothing more. Maybe Ebola’s different – maybe 90% effective screening can, for the most part, keep it off shore. But I wonder.