Tuberculosis epidemics driven by HIV: is prevention better than cure?

Area of Science:

• Epidemiology
• Public Health
• Mathematical Modeling

Background:

• High HIV prevalence significantly increases tuberculosis (TB) incidence.
• Effective TB control strategies are crucial in co-epidemic regions.
• Understanding the interplay between TB and HIV is essential for public health interventions.

Purpose of the Study:

• To compare the efficacy of active TB treatment versus TB and HIV prevention strategies.
• To evaluate interventions for TB control in areas with high HIV prevalence.
• To model the long-term impact of different control measures on TB and HIV.

Main Methods:

• Developed a compartmental difference equation model for TB and HIV.
• Utilized Bayesian methods to fit the model to time series and published data.
• Compared the effectiveness of TB chemotherapy against highly active antiretroviral therapy (HAART), latent TB infection treatment (TLTI), and HIV transmission reduction.

Main Results:

• Active TB case finding and treatment is the most effective short-term (10-year) strategy to reduce TB cases and deaths, even with high HIV prevalence.
• Highly active antiretroviral therapy (HAART) shows comparable effectiveness to active TB treatment, but requires very high coverage and compliance.
• Treatment of latent TB infection (TLTI) is largely ineffective across all time scales.
• Reducing HIV incidence is less effective for TB prevention over 10 years but becomes more impactful over 20 years.

Conclusions:

• TB control programs in high HIV prevalence settings must prioritize the treatment of active TB cases.
• TB prevention methods should be implemented alongside active case treatment for sustained, long-term TB control.
• Prevention strategies should augment, not substitute, active TB treatment for comprehensive disease management.