Isoniazid preventive therapy programmes for healthcare workers in India: translating evidence into policy

Occupational tuberculosis (TB) among healthcare workers (HCWs) is an important public health issue, especially in India where HCWs are exposed to a high burden of TB and infrastructural infection control procedures are inadequate. We examined the need for implementing isoniazid preventive therapy (IPT) programmes to protect Indian HCWs from occupational TB.

Bardach's 8-fold path was followed to analyse and formulate the policy for introducing IPT programmes for HCWs in India. The results of surveillance with tuberculin skin testing (TST) and treatment of latent TB infection with isoniazid (INH) for HCWs belonging to two different age groups (< or = 30 years and > 30 years) were compared with each other and with the alternative of maintaining status quo, i.e. no surveillance and no therapy, under various parameters such as the lifetime risks of active TB, deaths due to TB, benefit-risk ratios, cost-savings to the health system and relative risk reductions. RESULTS; The lifetime risk of TB was found to be higher among HCWs in the age group of < or = 30 years. IPT for HCWs reduced the lifetime risks of TB and death due to TB in both age groups, with better results in the age group of < or = 30 years. The relative lifetime risk reduction of active TB was 24.04% for the age group of < or = 30 years and 19.92% for the age group of > 30 years. The relative lifetime risk reduction of death due to TB by administration of IPT was from 13.96% to 19.62% in the two age groups. The benefit-risk ratio of IPT was 11.24 for the age group of < or = 30 years and 2.88 for the age group of > 30 years. IPT was associated with an approximate savings of rupee 4000-8000 for each case prevented.

TB is a major occupational hazard for Indian HCWs. The inclusion of IPT programmes in the national policy to combat TB, along with infrastructural infection control measures, can contribute to reduction in workplace TB. IPT programmes for HCWs in the younger age group have better results in terms of prevention of active TB, TB-related mortality and INH-induced hepatitis as compared to the older age group. There is an urgent need for a mechanism of targeted testing and treatment of latent TB infection to minimize the risk of occupational exposure for TB among HCWs in all age groups.