New Tuberculosis Vaccine Shows 50% Efficacy in Phase 2b Trial

M72/AS01E could be first new TB vaccine in a century, targeting world's deadliest infectious disease

After nearly a century without significant advancement, tuberculosis vaccine development has reached a watershed moment. The M72/AS01E vaccine candidate has demonstrated approximately 50% efficacy against pulmonary TB in adults with latent M. tuberculosis infection — a result that could save millions of lives if confirmed in larger trials.
The significance cannot be overstated. Tuberculosis kills more people than any other infectious disease, including HIV/AIDS and malaria. The existing BCG vaccine, developed over 100 years ago, provides limited protection in adults — precisely the population most at risk of developing active, transmissible disease. A vaccine that prevents pulmonary TB in adults would transform global health.
The 50% efficacy figure, reported from a Phase 2b trial, exceeds the threshold many experts considered necessary for a viable TB vaccine. It suggests that the immune system can be trained to recognize and combat M. tuberculosis before it establishes active infection — something the BCG vaccine largely fails to do in adults.
For high-burden countries where TB remains a leading cause of death, this represents hope for a different future. For the global health community, it validates decades of research and investment in a notoriously difficult vaccine target.

Key Facts

• Vaccine: M72/AS01E tuberculosis vaccine candidate
• Efficacy: ~50% against pulmonary TB in Phase 2b trial
• Target population: Adults with latent M. tuberculosis infection
• Current vaccine: BCG (developed >100 years ago, limited adult protection)
• TB status: World's leading infectious disease killer
• Source: GAVI VaccinesWork, AJMC

Why This Matters

TB has defied vaccine development for decades. The bacterium's complex lifecycle, ability to establish latent infection, and genetic sophistication make it a challenging target. Previous vaccine candidates have failed in late-stage trials, creating a field marked by cautious optimism at best. The M72/AS01E candidate, building on lessons from previous attempts and using a novel adjuvant system (AS01), has shown the most promising results to date. If Phase 3 trials confirm these findings, this would be the first new TB vaccine since BCG.

What We Don't Know Yet

Phase 2b results, while promising, require confirmation in larger Phase 3 trials. The 50% efficacy, while clinically meaningful, leaves significant protection gaps — complementary interventions will still be needed. The vaccine targets those with latent infection, not primary prevention of initial infection. Manufacturing scale-up for global distribution would be a massive undertaking. Cost and access in low-income countries, where TB burden is highest, remain uncertain. HIV-positive individuals, among the most vulnerable to TB, were excluded from this trial.

Published April 16, 2026 · Category: Health & Medicine