Despite enduring over a century with only one major tuberculosis (TB) vaccine, the global health community may soon witness a significant shift. With over a million lives lost annually to TB, scientists are on the brink of introducing new vaccines that promise to extend protection to adolescents and adults, a demographic previously vulnerable to this ancient scourge.
Tuberculosis, a disease that once claimed nearly a quarter of lives in Europe and North America centuries ago, continues to pose a severe threat worldwide. In 2022 alone, TB afflicted more than 10 million people globally, resulting in 1.3 million deaths, marking it as the second most lethal infectious disease that year, following closely behind COVID-19. The disease disproportionately affects low- and middle-income countries, where malnutrition and HIV prevalence exacerbate the risk of infection.
The current TB prevention strategy is anchored by the Bacille Calmette-Guérin (BCG) vaccine, first administered in 1921. While this vaccine has been instrumental in reducing TB incidence among infants, its efficacy diminishes over time, leaving older children and adults susceptible. Moreover, the BCG vaccine’s protection does not extend to pulmonary TB, the most contagious form of the disease, which predominantly affects the lungs and is the major contributor to TB morbidity and mortality worldwide.
Recognizing these limitations, researchers like Helen McShane, a professor of vaccinology at the University of Oxford, have been diligently working to develop more effective vaccines. The push for new vaccines has gained momentum, fueled by the alarming rise in drug-resistant TB strains that threaten to undermine decades of progress. Currently, several promising candidates are undergoing phase 3 trials, the final stage before potential approval by regulatory bodies such as the FDA and WHO.
Among these, the M72/AS01E vaccine, supported by the Bill and Melinda Gates Foundation, has shown considerable promise. In initial trials, it demonstrated a 54 percent efficacy in preventing active TB in infected adults—a significant breakthrough given the historical challenges of vaccine development against mycobacterial diseases.
While these developments offer hope, experts like Eliud Wandwalo of the Global Fund to Fight AIDS, Tuberculosis and Malaria caution that the new vaccines, even if successful, will not be a panacea. Comprehensive strategies that include improvements in sanitation, healthcare infrastructure, and ongoing treatment regimens will remain essential. Nonetheless, the potential introduction of more effective vaccines represents a critical advancement in the global fight against TB, raising optimism that eradication of the disease could be within reach within our lifetimes.