Efficacy of secondary isoniazid preventive therapy among HIV-infected Southern Africans: time to change policy?

AIDS. 2003 Sep 26;17(14):2063-70. doi: 10.1097/00002030-200309260-00007.


Objective: To determine the efficacy of secondary preventive therapy against tuberculosis (TB) among gold miners working in South Africa.

Design: An observational study.

Setting: Health service providing comprehensive care for gold miners.

Methods: The incidence of recurrent TB was compared between two cohorts of HIV-infected miners: one cohort (n = 338) had received secondary preventive therapy with isoniazid (IPT) and the other had not (n = 221).

Results: The overall incidence of recurrent TB was reduced by 55% among men who received IPT compared with those who did not (incidence rates 8.6 and 19.1 per 100 person-years, respectively; incidence rate ratio, 0.45; 95% confidence interval 0.26-0.78). The efficacy of isoniazid preventive therapy was unchanged after controlling for CD4 cell count and age. The number of person-years of IPT required to prevent one case of recurrent TB among individuals with a CD4 cell count < 200 x 106 cells/l, and > or = 200 x 106 cells/l was 5 and 19, respectively.

Conclusion: Secondary preventive therapy reduces TB recurrence: the absolute impact appears to be greatest among individuals with low CD4 cell counts. International TB preventive therapy guidelines for HIV-infected individuals need to be expanded to include recommendations for secondary preventive therapy in settings where TB prevalence is high.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Distribution
  • Antitubercular Agents / therapeutic use*
  • Blacks
  • CD4 Lymphocyte Count / methods
  • Cohort Studies
  • Gold
  • HIV Infections / complications*
  • HIV Infections / epidemiology
  • Humans
  • Incidence
  • Isoniazid / therapeutic use*
  • Male
  • Middle Aged
  • Mining*
  • Occupational Diseases / complications
  • Occupational Diseases / epidemiology
  • Occupational Diseases / prevention & control*
  • Secondary Prevention
  • South Africa / epidemiology
  • Tuberculosis / complications
  • Tuberculosis / epidemiology
  • Tuberculosis / prevention & control*


  • Antitubercular Agents
  • Gold
  • Isoniazid