Effect Measure

CDC describes its No Fly list — sort of

Generals are often said to be fighting the last war and public health officials likewise are managing the last crisis. At the end of May 2007 we had the notorious flying lawyer with TB flap (see our multiple posts here), so in June 2007 CDC quietly instituted their public health version of the “No Fly” list. I guess because the Department of Homeland Security (DHS) No Fly list has been so incompetently and dangerously implemented CDC didn’t want to taint their version with the same name, so they are calling it the Do Not Board (ENB) list. The DHS list is pushing a million entries. Pretty soon the airlines won’t have to worry about fuel costs because we will all be on the No Fly list (maybe just saying that is enough to get me on the list). The CDC DNB list is much smaller. Since its inception a little over a year ago, 33 people have been turned away for being a communicable disease risk to others. Maryn McKenna at Superbug has an excellent post up that asks some very pertinent questions (her blog is one of the main places to look if you are interested in MRSA, too). So what does the DNB involve?

The public health DNB list is intended to supplement local public health measures when they are deemed insufficient to prevent persons who are contagious from boarding commercial aircraft. Use of the list is limited to diseases that would pose a serious health threat to fellow air travelers. The list is authorized under the Aviation and Transportation Security Act of 2001* and is managed jointly by DHS and CDC; however, DHS defers to CDC regarding public health decisions and actions.

To request that a person be placed on the public health DNB list, state or local public health officials contact the CDC Quarantine Station for their region†; health-care providers make requests by contacting their state or local public health departments, and foreign and U.S. government agencies contact the Director’s Emergency Operations Center (DEOC) at CDC in Atlanta. To include someone on the list, CDC must determine that the person 1) likely is contagious with a communicable disease that would constitute a serious public health threat should the person be permitted to board a flight; 2) is unaware of or likely to be nonadherent with public health recommendations, including treatment; and 3) likely will attempt to board a commercial aircraft. Once a person is placed on the list, airlines are instructed not to issue a boarding pass to the person for any commercial domestic flight or for any commercial international flight arriving in or departing from the United States. The public health DNB list does not apply to other means of transportation (e.g., buses or trains). Governments of foreign countries are notified when their citizens or persons residing in their countries are placed on the list. (Morbidity and MOrtality Weekly Reports [MMWR], CDC)

Unfortunately this is not as clear as it could or should be. Are the three criteria — 1) likely is contagious with a communicable disease that would constitute a serious public health threat should the person be permitted to board a flight; 2) is unaware of or likely to be nonadherent with public health recommendations, including treatment; and 3) likely will attempt to board a commercial aircraft — all required? The word “and” appears before the third one, suggesting this is so, but it is unlikely many people would have all of this information available. A wide range of diseases are possible as pretexts for getting on the DNB, but it has been used only for one, tuberculosis. It is obvious that this was a device targeted to this disease but while they were at it, CDC spread the net wider — much wider. There is precious little evidence of risk from traveling TB cases, the only examples being on very long flights, not flights typically in the domestic US.

It’s not clear exactly how one gets on the list. There is a list of considerations but no details on how determinations are made, by whom and what is considered sufficient. Many people are diagnosed with TB daily in the US but only 33 got on the list in 15 months. What was it about those 33? Most were not drug resistant cases, according to CDC. CDC says they were “thought to have” infectious tuberculosis (on what grounds?). Drug sensitivity tests were available for most of them (27/33) and of those, 70% were infected with drug sensitive TB. Seven had multiple drug resistant (MDR) TB. One had extensively resistant XDR TB, an infection with TB resistant to most of the available drugs. The lawyer whose case started all this was thought to have been an XDR case but later was determined to be the slightly less serious (but still serious) MDR TB. Almost half were citizens of areas with a high rate of endemic TB.

More importantly, how does one get off the list? Since the DHS No Fly list seems like a chronic disease for any traveler unfortunate enough to contract it, getting off the CDC DNB is a key question. CDC says 10 have already been taken off the list and a process of review is in place:

Public health officials who request placement of a person on the public health DNB list are asked to notify their CDC Quarantine Station as soon as the person on the list is determined to be noncontagious. Once public health authorities confirm that a person is no longer contagious, CDC and DHS remove the person from the list, typically within 24 hours. In addition, on a monthly basis, CDC reviews all persons on the public health DNB list to determine whether they are eligible for removal. During June 2007–May 2008, 18 (55%) of the 33 persons placed on the public health DNB list later were removed because they were determined either to be no longer contagious or not to have TB. Persons removed during this period had been on the public health DNB list for a median of 26 days (range: 2–193 days). The 15 persons not removed had been on the public health DNB list for a median of 72 days (range: 1–364 days).

This is sounds reassuring. But I regret to say that written safeguards have too often been ignored by this administration and they no longer deserve the benefit of the doubt.

And these aren’t the only questions. Maryn McKenna wonders about privacy considerations, accuracy and scope. The notorious lawyer case from 2007, a case where CDC’s missteps brought it some very bad publicity, seems to have been the occasion for the agency to assume rather broad powers without much public discussion. This has the appearance of a blunt instrument that could be applied inconsistently, capriciously or for ulterior motives (i.e., for reasons unconnected with a health threat). The Bush administration and agencies it has politicized like CDC have brought these suspicions on themselves.

The big question for us is whether civil liberties will once again become collateral damage as CDC fights the last crisis while turning a blind eye to the state of public health more generally.


  1. #1 TEX
    September 20, 2008

    Lots written here, with some missed points. Active TB disease is active TB disease, with the particular strain and corresponding drug sensitivities/ susceptibilities irrelevent (PAN-sensitive vs MDR vs XDR, etc). Certainly, the TREATMENT of different strains is different, but that shouldn’t diminish the fact that any TB is a threat to an individual and the public’s health.
    Determining whether active TB diseased person is “infectious” is a crude test (not the lab test, but the sputum collection method) and shouldn’t be the cornerstone for determining infectiousness. A person isn’t cured of TB until AFTER completion of drug therapy. It is impossible to truly determine when a TB case is no longer infectious, each person is different and TB bugs are proven to be tough to kill (in the body).
    TB case management is handled at the LOCAL level by local TB controllers, and sometimes the state level, each state is different. The TB case referenced here was taken on by the CDC because it became international, and because of the obvious failure of the local TB controller (and/or possibly weak GA state statutes).
    In the U.S., controlling the inherent freedoms of individuals is serious business and involves complicated legal proceedings to involuntarily isolate a person infected with a communicable condition.
    As a former TB controller, the ENB list would have been very useful to control the spread, even if it’s only the POTENTIAL spread of TB….as long as the process can be completed very, very quickly. It is proven that different individuals react different after exposure to TB. On an airplane, under normal conditions (read: normal passengers with tact immune systems), yes, low risk. But there is a host of risk categories that make individuals more susceptible to infection after exposure, i.e HIV-positive, infants, elderly, and other immuno-compromising conditions.
    And yes, while an American’s civil liberties are the envy of the world, our public health system is not. Public health in the U.S. is deemed wimpy by the public and unimportant and ineffective by political leaders and policy makers. It is a good thing if public health in the U.S. would be important again and do it’s job of protecting the health of the public. The cornerstone of public health-like problems and subsequent interventions should be science, not politics or an individuals personal views, and the decisions should be more conservative….meaning, there should be no risk to the public versus allowing a little risk (i.e. “…little evidence of risk from traveling TB cases.”).

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