Correspondence
Changes in the Transmission of Tuberculosis in New York
N Engl J Med 2002; 347:1453-1455October 31, 2002
- Article
To the Editor:
According to the article by Geng et al. (May 9 issue),1 the majority of cases of active tuberculosis in the New York City area are now reactivation cases in recently arrived immigrants. However, current guidelines advise chemoprophylaxis only in people 35 years of age or younger.2 How should we use the current information3 in advising therapy for immigrants older than 35 who have a positive skin test with purified protein derivative, chest radiographs that show no abnormalities, and no evidence of underlying immune compromise?
3 ReferencesArthur W. Hammer, M.D.
Beth Israel Hospital, Brooklyn, NY 12234
arthurhdoc@hotmail.com 1
Geng E ,Kreiswirth B ,Driver C , et al. Changes in the transmission of tuberculosis in New York City from 1990 to 1999. N Engl J Med 2002;346:1453-1458
Full Text | Web of Science | Medline2
Update: fatal and severe liver injuries associated with rifampin and pyrazinamide for latent tuberculosis infection, and revisions in American Thoracic Society/CDC recommendations -- United States, 2001. Am J Respir Crit Care Med 2001;164:1319-1320
Web of Science3
Targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:Suppl:S221-S247
Web of Science | Medline
To the Editor:
Geng and colleagues use their finding of a strain of Mycobacterium tuberculosis in one or several patients (unique or part of a cluster) to distinguish reactivation from cross-infection. Initially, any cluster must have had a single member. Left long enough, a unique carrier would infect others and become part of a cluster. The number of unique patients and patients in a cluster will therefore vary with the intensity of surveillance, which may be greater for immigrants than for U.S.-born persons. If a major source of infection is immigration, we might expect to find an immigrant in most clusters. In clusters without an immigrant, it is arguable that there was reactivation in a home-born member. It would be interesting to know how many clusters there were of each kind.
T.H. Hughes-Davies, F.R.C.P.
Breamore Marsh, Fordingbridge, Hampshire SP6 2EJ, United Kingdom
thhd@thhd.fsnet. co. uk To the Editor:
An important population in which the problem of “poor acceptance and completion rates for treatment of latent [tuberculosis] infection” is evident is the growing population of foreign-born or foreign-trained health care professionals. Many have a history of bacille Calmette–Guérin (BCG) vaccination in infancy, and a blind faith in their vaccination seems to prevent them from availing themselves of treatment for latent tuberculosis infection to prevent active tuberculosis.1
Since the 1920s, BCG has been given to children in developing countries, including most on the current World Health Organization (WHO) list of tuberculosis “hot spots.” Approximately 100 million children receive BCG annually, and most experts agree that it is highly variable in protecting adults against tuberculosis.2 Furthermore, tuberculin reactions from BCG given in infancy invariably wane within five years.3
According to the recent American Thoracic Society–Centers for Disease Control and Prevention statement, endorsed by the Infectious Diseases Society of America and the American Academy of Pediatrics, “No method can reliably distinguish tuberculin reactions caused by BCG from those caused by natural mycobacterial infections. Therefore a positive reaction to tuberculin in BCG vaccinated persons indicates infection with M. tuberculosis when the person tested is at increased risk for recent infection.”4 If this simple fact were accepted by foreign-trained physicians and their employers (as a condition of employment), such physicians could become true role models, both in accepting indicated treatment for themselves and in educating their patients.
4 ReferencesLee B. Reichman, M.D., M.P.H.
New Jersey Medical School National Tuberculosis Center, Newark, NJ 07101-1709
reichmlb@umdnj.edu 1
Reichman LB, Tanne JH. Timebomb: the global epidemic of multi-drug-resistant tuberculosis. New York: McGraw-Hill, 2002:34.
2
Fine PEM. BCG vaccines and vaccination. In: Reichman LB, Hershfield ES, eds. Tuberculosis: a comprehensive international approach. 2nd ed. Vol. 144 of Lung biology in health and disease. New York: Marcel Dekker, 2000:505-7.
3
Reichman LB, Hershfield ES, eds. Tuberculosis: a comprehensive international approach. 2nd ed. Vol. 144 of Lung biology in health and disease. New York: Marcel Dekker, 2000:290-1.
4
Targeted tuberculin testing and treatment of latent tuberculosis infection. MMWR Morb Mortal Wkly Rep 2000;49:24-25
To the Editor:
Geng and colleagues showed, using DNA fingerprinting, that bacillary tuberculosis in foreign-born persons in New York is largely due to reactivation of latent infection with M. tuberculosis. Even in the tuberculosis-endemic Chingleput district of southern India, epidemiologic studies have shown that tuberculosis in adults is predominantly reactivation disease.1,2 In the Perspective accompanying the report by Geng et al., Bloom3 highlights the imperative of tuberculosis control in developing countries and echoes the WHO approach — namely, detection of at least 70 percent of cases and cure in at least 85 percent of them. This approach will result in cure in only 60 percent of cases. Even persons receiving treatment would already have infected others before diagnosis and treatment.4
Most new infections are in children. Thus, even with detection and treatment, children will continue to become infected and, years later, to have reactivation disease. If we do not control the progression to reactivation in the pool of infected children, we lose a window of opportunity to reduce future disease and consequent transmission.2 Originally, BCG inoculation was intended to reduce childhood infection with M. tuberculosis.1 The Chingleput vaccine trial and other studies have clearly shown that BCG vaccination does not prevent infection.1,2,4 Therefore, the global tuberculosis-control strategy must include screening of children for infection. If children who are in contact with infected adults are found to be infected, they should be given preventive chemotherapy to reduce the future risk of reactivation disease; all children should be screened at periodic intervals (for example at 5, 10, and 15 years of age); and recently infected children should also be given preventive chemotherapy. Such an approach would not only be good clinical pediatrics; it would also be good public health.
4 ReferencesT. Jacob John, F.R.C.P., Ph.D.
439 Civil Supplies Godown Ln., Vellore, TN, 632 002, India
vlr_tjjohn@sancharnet.in 1
Tuberculosis Research Centre (ICMR)
Web of Science | Medline2
John TJ . Tuberculosis control, without protection from BCG. Indian Pediatr 2000;37:9-18
Medline3
Bloom BR . Tuberculosis -- the global view. N Engl J Med 2002;346:1434-1435
Full Text | Web of Science | Medline4
Neuenschwander BE ,Zwahlen M ,Kim SJ ,Lee EG ,Rieder HL . Determination of the prevalence of infection with Mycobacterium tuberculosis among persons vaccinated with Bacillus Calmette-Guerin in South Korea. Am J Epidemiol 2002;155:654-663
CrossRef | Web of Science | Medline
Author/Editor Response
The authors reply:
To the Editor: John points out the limited success of BCG vaccination in reducing cases of tuberculosis in highly endemic areas and urges that in such areas, widespread screening for and treatment of latent tuberculosis infection be instituted to reduce the risk of reactivation and thus progression to active disease. We agree that treatment of latent infection has been overlooked as a control strategy in countries with a high prevalence of tuberculosis. However, current approaches to the treatment of latent infection are far from ideal, since they rely mainly on prolonged self-administration of isoniazid in a schedule of 270 daily doses. Shorter-duration regimens, which can be delivered by directly observed therapy (such as a 12-dose regimen of once-weekly isoniazid and rifapentine) are needed and are being studied in large, controlled trials.
Much confusion persists regarding interpretation of the results of tuberculin skin tests in persons who have received the BCG vaccine — a problem that can lead to missed opportunities for tuberculosis prevention, as Reichman ably points out in his letter. There is no question that a positive skin test in an adult who was vaccinated with BCG at birth almost certainly represents true latent tuberculosis infection.1 Health care personnel with latent tuberculosis infection should in general receive high priority for treatment of latent infection, since they can easily spread disease to vulnerable patients.2
Hughes-Davies addresses methodologic issues inherent in all molecular epidemiologic studies of tuberculosis (and epidemiologic studies in general). These caveats are well recognized.3,4 Hughes-Davies also raises the possibility that in our study, clusters may have often been started by non–U.S.-born persons, therefore implying that non–U.S.-born persons contributed more to ongoing transmission than we recognized. We believe this an unlikely possibility. Twenty of 51 clusters consisted solely of U.S.-born persons, and only 7 were made up solely of foreign-born persons. Of the 24 clusters containing both U.S.- and foreign-born persons, the index cases (defined as those with the earliest date of diagnosis relative to others in the cluster) were U.S.-born in 17, and the mean size of those clusters was 9.1 persons. In contrast, clusters containing only non–U.S.-born persons contained a mean of 2.8 persons. The long period over which cases were collected, as well as the high capture rate in our area (77 percent of isolates), makes our results robust.
4 ReferencesElvin Geng, M.D., M.P.H.
Neil Schluger, M.D.
Columbia University College of Physicians and Surgeons, New York, NY 100321
Menzies D . What does tuberculin reactivity after bacille Calmette-Guerin vaccination tell us? Clin Infect Dis 2000;31:Suppl 3:S71-S74
CrossRef | Web of Science | Medline2
Targeted tuberculin testing and treatment of latent tuberculosis infection. Am J Respir Crit Care Med 2000;161:Suppl:S221-S247
Web of Science | Medline3
Glynn JR ,Vynnycky E ,Fine PE . Influence of sampling on estimates of clustering and recent transmission of Mycobacterium tuberculosis derived from DNA fingerprinting techniques. Am J Epidemiol 1999;149:366-371
Web of Science | Medline4
Murray M ,Alland D . Methodological problems in the molecular epidemiology of tuberculosis. Am J Epidemiol 2002;155:565-571
CrossRef | Web of Science | Medline
- Citing Articles (1)
Citing Articles
1
Óscar Sanz-Peláez, José A. Caminero-Luna, José L. Pérez-Arellano. (2006) Tuberculosis e inmigración en España. Evidencias y controversias. Medicina Clínica 126:7, 259-269
CrossRef
