Tuberculosis vaccination versus isoniazid preventive therapy: a decision analysis to determine the preferred strategy of tuberculosis prevention in HIV-infected adults in the developing world.
METHODS
The developing world.


OBJECTIVE
To compare the strategy of TB vaccination with that of tuberculin skin-testing in conjunction with isoniazid (INH) in preventing tuberculosis in HIV-infected persons. For any clinical scenarios in which immunization would be more effective than INH preventive therapy, to determine the minimum necessary vaccine safety and effectiveness required.


METHODS
Decision analysis. A hypothetical cohort of 10000 HIV-infected persons, 65% of whom were tuberculin positive, living in the developing world, was studied. Probability estimates were based on BCG vaccine for the baseline analysis, and it was assumed that the vaccine cannot protect if given after infection.


RESULTS
Under the probability estimates and assumptions of the analysis, tuberculin skin testing/INH preventive therapy would prevent 458 more cases of TB and 45 more deaths due to TB than TB vaccination. One- and two-way sensitivity analyses revealed no thresholds at which TB vaccination would be the preferred strategy. Vaccine safety did not impact the outcome of the analysis. Three-way sensitivity analysis revealed that if the prevalence of anergy were 35% and the risk of progression to active TB among anergic persons 12.2 cases per 100 person-years, a vaccine would have to be at least 87% effective to be preferred over INH preventive therapy.


CONCLUSIONS
Under the conditions of the analysis, which did not account for cost or logistics, tuberculin skin testing/INH preventive therapy would be more effective than TB vaccination in preventing TB among HIV-infected persons. The hypothesized TB vaccine would prevent more TB than INH preventive therapy only in areas where the prevalence of anergy and risk of active TB if anergic were high, and vaccine effectiveness exceeded 87%.
Sterling
T R
TR
Department of Medicine, Keesler Medical Center, Keesler AFB, Mississippi, USA. tsterls@welchlink.welch.jhu.edu
Brehm
W T
WT
Moore
R D
RD
Chaisson
R E
RE
D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use*; D001500:BCG Vaccine / Q000627:therapeutic use*; D003661:Decision Support Techniques; D003906:Developing Countries; D015658:HIV Infections / Q000150:complications; D006801:Humans; D016867:Immunocompromised Host; D007538:Isoniazid / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000276:immunology / Q000517:prevention & control*
D000995:Antitubercular Agents; D001500:BCG Vaccine; D007538:Isoniazid