Phillips, Carlile and Smith are to be commended for their description
of the “Epidemiology of a Tuberculosis Outbreak in a Rural Missouri High
School” (Pediatrics 2004; 113:e514-e519) which serves as useful reminder
of the importance of public health measures necessary for preventing the
spread of tuberculosis.
The data they present contains some disturbing implications which the
authors have not discussed:
* Approximately 135 students never completed testing. While there
may be some comfort in the information that none of 87 “highest risk”
students who did not complete testing in September 2001 but were later
tested were positive, the risk of a positive test in the untested group
appears to be about 10%. While the reported 5-year risk of developing
tuberculosis in untreated LTBI is 2.4% (1), if disease should occur in
members of this group, diagnosis is likely to be delayed. Continued
effort to find and test these individuals should be made, but such efforts
require appropriate resources.
* 33 of 453 (7.3%) tested students who did not share a class with
the index case had a positive PPD. This is certainly consistent with
reports of transmission of TB during a long airplane ride. (2) However,
few pediatricians would identify attending a school, but not a class,
where a student had active tuberculosis as a reason for screening. This is
a circumstance where alerting pediatricians and other pediatric health
care providers might be helpful. To be effective such an alert would need
to identify the school involved – an invasion of privacy which needs to be
balanced against public health concerns. The AAP Committee on Infectious
Diseases may also wish to modify their Recommendations for Pediatric
Screening for TB in light of these findings and similar past reports
(3,4,5).
* At least 8 of 87 faculty had a positive PPD. This implies that
faculty, including faculty without obvious contact with an infectious
student, are at risk. While the total number of school faculty tested is
not mentioned, the difference between the numbers in Table 1 and Table 2
(77) suggest that 10 faculty may not have been tested. The state and
legislature need to consider whether it is appropriate for TB-exposed
school faculty to continue having contact with students without testing.
Josiah Wedgwood MD PhD
Division of Allergy Immunology and Transplantation,
National Institute of Allergy and Infectious Diseases,
Bethesda, MD*
* For identification purposes only. The views are solely those of
the author.
1. Comstock GW. How much isoniazid is needed for prevention of
tuberculosis among immunocompetent adults? Int J Tuberc Lung Dis 1999;
3:847-850.
2. Kenyon T, Valway S, Ihle W, Onorato I, Castro K. Transmission of
multidrug-resistant mycobacterium tuberculosis during a long airplane
flight. N Engl J Med 1996; 324; 15: 933-8.
3. Sacks JJ, Brenner ER, Breeden DC, Anders HM, Parker RL.
Epidemiology of a tuberculosis outbreak in a South Carolina junior high
school. Am J Public Health 1985; 75:361-365.
4. Curtis AB, Ridzon R, Vogel R, McDonough S, Hargreaves J, Ferry J,
Valway S, Onorato IM. Extensive Transmission of Mycobacterium tuberculosis
from a Child. N Engl J Med 1999; 341:1491-1495.
5. Sepkowitz KA. How contagious is tuberculosis? Clin Infect Dis
1996; 23:954-962.
Conflict of Interest:
None declared
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