Reports on HIV/AIDS: 1990

MAY 18, 1990, MMWR, Vol. 39, RR-8: [inclusive page numbers]
The Use of Preventive Therapy
for Tuberculous Infection
in the United States
Recommendations of the Advisory Committee
for Elimination of Tuberculosis
INTRODUCTION
The appropriate use of preventive therapy will play a crucial role in efforts to
eliminate tuberculosis in the United States by the year 2010 (1). When taken as
prescribed, isoniazid preventive therapy is highly effective in preventing latent
tuberculous infection from progressing to clinically apparent disease. In controlled
trials conducted by the Public Health Service in ordinary clinical and public health
settings, isoniazid preventive therapy reduced the incidence of disease by 54%-88%
(2). The main reason for the variation in efficacy appears to have been the amount of
medication actually taken during the year in which isoniazid was prescribed. In a trial
conducted in eastern Europe among infected adults with abnormal chest radiographs, a 12-month course of isoniazid preventive therapy was 75% effective among
all persons assigned to the regimen and 93% effective among those who were
compliant with therapy (3). Similarly, isoniazid preventive therapy was estimated to
be 98% effective among children in Houston and in recently infected nursing home
patients who were compliant with therapy (4,5). Isoniazid preventive therapy has
been shown to be effective for long periods and to be reasonably cost-effective (6,7).
Despite its proven effectiveness, preventive therapy is less widely applied in the
United States than it should be. Reports submitted to CDC by tuberculosis control
programs in states and large cities indicate that <60% of infected contacts of persons
with newly diagnosed tuberculosis are being started on preventive therapy (CDC,
unpublished data). In a study to determine why tuberculosis is not prevented,
investigators found that in a high proportion of newly diagnosed cases the opportunity to prevent disease had been missed (8). Although three-fourths of the persons
surveyed had contact with a health-care provider within the 5 years before the most
recent diagnosis of tuberculosis, less than one-third of them had been tuberculin skin
tested even though many had risk factors for tuberculosis. Of the persons who had
positive skin tests and other factors placing them at increased risk of disease, only 5%
had been offered preventive therapy.
The following recommendations of the Advisory Committee for Elimination of
Tuberculosis (ACET) are intended to increase the effective application of preventive
therapy in the United States. Health departments, medical and nursing schools,
schools of public health, voluntary agencies, and professional societies may use
these guidelines to educate health-care providers about the appropriate use of
preventive therapy in efforts to eliminate tuberculosis. The ACET recognizes that
clinical decisions regarding preventive therapy must be individualized and based on
an assessment of benefits and risks. These recommendations are intended to assist
physicians and patients in making these decisions.

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