Tuberculosis remains one of the world’s most persistent infectious diseases, caused by Mycobacterium tuberculosis and spread primarily through airborne droplets. Despite being preventable and treatable, tuberculosis continues to challenge global health systems due to drug resistance, co-infections, and socioeconomic factors.

Vaccine-based strategies are central to global prevention efforts, with research focusing on new-generation vaccines and improved therapeutic approaches.

The Role of BCG and Its Limitations

The Bacillus Calmette–Guérin (BCG) vaccine, introduced over a century ago, is the most widely used tuberculosis vaccine. It offers strong protection for children against severe forms of the disease, such as miliary TB and TB meningitis. However, its effectiveness against adult pulmonary TB—the most contagious form—varies significantly across populations. This inconsistency is influenced by environmental mycobacteria exposure, genetic differences, and varying immune responses.

Due to these limitations, scientists are working to develop more reliable vaccines capable of preventing infection, halting progression from latent to active disease, or boosting immunity post-infection.

Advancements in Vaccine Research

Modern research is exploring diverse vaccine candidates including subunit vaccines, recombinant viral vector vaccines, and live attenuated strains. Some vaccines aim to enhance immunity in individuals who already received BCG, while others seek to replace BCG entirely. Novel approaches target antigens expressed in different phases of infection, including latent TB, aiming to disrupt bacterial persistence.

Recombinant technologies allow the development of vaccines that express multiple antigens simultaneously, promising broader immune activation. Meanwhile, therapeutic vaccines are being studied to help patients undergoing drug treatment, reducing relapse rates and potentially shortening treatment duration.

Global Challenges in Tuberculosis Control

Drug-resistant TB remains a major obstacle, especially in regions with limited healthcare access. Multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) require long, complicated treatment regimens with significant side effects. New vaccines could drastically reduce transmission, easing the global burden of resistant strains.

Latent tuberculosis infection, affecting nearly one-quarter of the global population, presents another challenge. People with latent infection show no symptoms but can develop active disease at any time. Future vaccines aim to prevent this reactivation.

Public Health Strategies and Global Impact

National TB programs incorporate vaccination, screening, early diagnosis, and timely treatment into coordinated strategies. Education campaigns, improved ventilation in crowded environments, and better diagnostic tools—such as molecular testing—support prevention. Vaccine innovation is expected to become a cornerstone of future elimination efforts.

FAQs

1. Why isn’t BCG sufficient for adults?Its efficacy varies widely, especially against pulmonary TB, due to environmental and immunological differences.

2. Are new TB vaccines being developed?Yes, dozens of candidates are in clinical trials focusing on prevention, improved immunity, and therapeutic support.