New tuberculosis vaccines for people with HIV

Area of Science:

• Epidemiology
• Vaccinology
• Mathematical Modeling

Background:

• Tuberculosis (TB) remains a major cause of death in people with HIV (PWH), with 160,000 deaths in 2024.
• Several novel TB vaccines are under development, necessitating strategies for their optimal deployment.
• The most effective vaccination approach to reduce TB burden in PWH, considering diverse global settings, is currently unknown.

Purpose of the Study:

• To model the impact of new TB vaccines on reducing TB incidence in PWH across 15 high-burden countries.
• To evaluate how vaccination impact varies based on HIV prevalence, ART coverage, and vaccine efficacy in different populations.
• To determine the most efficient vaccination strategies for PWH.

Main Methods:

• A mathematical model was employed to simulate TB vaccination scenarios.
• Simulations were conducted in 15 countries with high TB and HIV burdens.
• Vaccine efficacy assumptions varied by HIV status and ART coverage to assess impact on TB disease.

Main Results:

• Vaccines not effective in PWH could avert 5-13% of TB cases in PWH via indirect effects.
• Vaccines equally effective in PWH and HIV-uninfected individuals could avert 19-25% of TB cases in PWH.
• Vaccination strategies targeting PWH showed greater efficiency and impact, particularly in settings with high ART coverage.

Conclusions:

• Optimal TB vaccine deployment in PWH depends on country-specific factors like ART coverage and vaccine efficacy in PWH.
• Vaccinating PWH is likely an efficient strategy to decrease TB burden in this population.
• Targeted vaccination of PWH may be more impactful than vaccinating HIV-uninfected individuals in high ART coverage settings.