It takes “10 hours … on average” for the Centers for Disease Control and Prevention (CDC) to place persons known or strongly believed to have a highly infectious disease like tuberculosis (TB) on the public health Do Not Board (DNB) list which is supposed to bar them from boarding commercial aircraft departing from or arriving in the United States, according to CDC documents.

Although the public health DNB list was authorized under the Aviation and Transportation Security Act of 2001, it wasn’t until after concerns about infectious diseases monitoring were highlighted following the failure of the Department of Homeland Security (DHS) and Department of Health and Human Services’ (HHS) authorities to stop two people (including a Mexican businessman from Juarez, Mexico who’d repeatedly criss-crossed the US/Mexican border in the spring of 2007) with TB exiting and entering the US for the government to finally cobble together the DNB process nearly seven years later.

The DNB listing process enables domestic and international public health officials to request that persons with communicable diseases who meet specific criteria and pose a serious threat to the public be put on the list and restricted from flying.

The list is limited to diseases that would pose a serious health threat to commercial aircraft passengers and is jointly managed by CDC and DHS. DHS defers to CDC regarding what public health actions to take.

The DNB list is a vital tool used by public health officials to prevent travel on commercial aircraft by persons who pose a risk of infecting other travelers. The list supplements local public health infectious disease containment measures when they are unable to prevent persons carrying a highly contagious disease from boarding commercial aircraft.

Indeed, among the reasons for implementing the DNB list was the concern that there is “reason to believe [an] individual would not comply with public health guidance or public health authorities would be unable to locate the individual; the individual [is] unaware of the recommendation not to travel;” and “there [is] reason to believe that the individual would attempt to fly on a commercial aircraft.”

According to CDC, “two of the 33 persons on the public health DNB list during June 2007-May 2008 are known to have attempted to evade the US air travel restriction. Both persons were successfully detected by [Customs and Border Protection] CBP officers before they were admitted into the United States and were taken to local hospitals for evaluation and care of TB.”

Between June 2007 and May 2008, of the 42 persons the CDC was asked to put on the public health DNB list, seven (26%) had Multiple Drug-Resistant TB, and one had extensively drug-resistant TB.

Thirty-three (79%) of the 42 met the criteria to be placed on the DNB – they all were believed to have infectious pulmonary TB. Drug-susceptibility testing results were available for 27 (82%), of whom 19 (70%) were susceptible to first-line anti-TB medications.

An estimated two billion people—one-third of the world’s population—are infected with Mycobacterium (M.) tuberculosis, the bacterium that causes tuberculosis, approximately nine million of whom have transmissible TB disease.

Today, TB is the leading cause of infectious disease death among adults worldwide, and drug-resistant TB is rapidly becoming a particularly disturbing threat—there were nearly 500,000 new cases in 2006. There's about 40,000 new cases of extensively drug-resistant TB every year, according to the World Health Organization.

For US public health and security officials, the rise of tuberculosis and its drug-resistant sibling in Mexican border cities is especially alarming, particularly in the wake of at least two TB carriers having repeatedly crossed the border back and forth in 2007.

Requests for 28 (85%) of the 33 persons who were put on the DNB list between June 2007 and May 2008 came from state, territorial or local health departments, with the largest number of requests (seven) originating with Texas public health authorities.

Five requests came from California and three requests came from Canada, Mexico and the US Department of State. Fourteen persons (42%) were placed on the DNB list while outside the United States. Fifteen (45%) are citizens of countries designated by the World Health Organization as TB high-burden countries.

The Government Accountability Office (GAO) recently concluded that both agencies “should further strengthen their ability to respond to TB incidents.” They aren’t doing enough to ensure that TB-infected persons are disallowed from entering the United States, GAO reported.

At a meeting in June of CDC’s Advisory Council for the Elimination of Tuberculosis (ACET), Council members made a number of comments and suggestions for CDC to consider in finalizing the draft DNB and Lookout guidance. Over the past year, CDC’s Division of Global Migration and Quarantine (DGMQ) drafted a protocol with guiding principles and revised standard operating procedures for DNB and “Lookout Lists.”

Under Lookout List procedures, persons can be held at ports of entry pending a review of their cases by quarantine public health officers, but placement on this list alone does not prevent travel. The Lookout List can supplement or be issued separately from the DNB list.

The Council found that:

• Division of Tuberculosis Elimination should provide ACET with its algorithm to clear TB patients for air travel. This tool might assist domestic institutions on the ground in the control of patients with known or suspected Multiple Drug-Resistant-TB;
• DGMQ should inform all quarantine stations of the need to coordinate with the Immigration and Customs Enforcement (ICE) Health Service Program when DNB cases are placed into ICE custody. This approach will assure the continuity of care for ICE detainees;
• DGMQ should distribute a “Dear Colleague” letter to inform states that DNB and Lookout guidance will be published in an upcoming Morbidity and Mortality Weekly Report article. DGMQ should also urge states and quarantine stations to improve coordination with and better inform local health departments of available travel restriction tools and interventions, particularly since patients with known or suspected TB will be identified at the local level. Communication from DGMQ at the federal level to health departments at both state and local levels will enhance the flow and consistency of information. DNB and Lookout procedures widely vary among quarantine stations at this time.