High Incidence of Tuberculosis among HIV-Infected Infants: Evidence from a South African Population-Based Study Highlights the Need for Improved Tuberculosis Control Strategies

Background. There are limited population-based estimates of tuberculosis incidence among human immunodeficiency virus (HIV)-infected and HIV-uninfected infants aged <= 12 months. We aimed to estimate the population-based incidence of culture-confirmed tuberculosis among HIV-infected and HIV-uninfected infants in the Western Cape Province, South Africa. Methods. The incidences of pulmonary, extrapulmonary, and disseminated tuberculosis were estimated over a 3-year period (2004-2006) with use of prospective representative hospital surveillance data of the annual number of culture-confirmed tuberculosis cases among infants. The total number of HIV-infected and HIV-uninfected infants was calculated using population-based estimates of the total number of live infants and the annual maternal HIV prevalence and vertical HIV transmission rates. Results. There were 245 infants with culture-confirmed tuberculosis. The overall incidences of tuberculosis were 1596 cases per 100,000 population among HIV-infected infants (95% confidence interval [CI], 1151-2132 cases per 100,000 population) and 65.9 cases per 100,000 population among HIV- uninfected infants (95% CI, 56 75 cases per 100,000 population). The relative risk of culture-confirmed tuberculosis among HIV-infected infants was 24.2 (95% CI, 17-34). The incidences of disseminated tuberculosis were 240.9 cases per 100,000 population (95% CI, 89-433 cases per 100,000 population) among HIV-infected infants and 14.1 cases per 100,000 population (95% CI, 10-18 cases per 100,000 population) among HIV-uninfected infants (relative risk, 17.1; 95% CI, 6-34). Conclusions. This study indicates the magnitude of the tuberculosis disease burden among HIV-infected infants and provides population-based comparative incidence rates of tuberculosis among HIV-infected infants. This high risk of tuberculosis among HIV-infected infants is of great concern and may be attributable to an increased risk of tuberculosis exposure, increased immune-mediated tuberculosis susceptibility, and/or possible limited protective effect of bacille Calmette-Guerin vaccination. Improved tuberculosis control strategies, including maternal tuberculosis screening, contact tracing of tuberculosis-exposed infants coupled with preventive chemotherapy, and effective vaccine strategies, are needed for infants in settings where HIV infection and tuberculosis are highly endemic.