TB Vaccine: Reducing Global Risk & Inequality | Global Issues
A recent tuberculosis (TB) outbreak at Archbishop Riordan High School in San Francisco, identified in late January, has prompted a large-scale public health investigation and highlighted disparities in how TB risk is perceived and addressed globally.
The San Francisco Department of Public Health diagnosed three cases of active TB disease at the school and subsequently identified over 50 cases of latent TB infection, according to reports from the San Francisco Chronicle and Medical Xpress. The outbreak comes as California has seen a rise in TB cases since 2023.
While the San Francisco outbreak has generated significant local concern and media attention, experts note that TB remains a far greater threat in many parts of the world, particularly in sub-Saharan Africa. According to the Inter Press Service, an estimated 10.7 million people globally fell ill with TB in 2024 and the disease killed 1.23 million – more than any other infectious disease.
“Unfortunately, most cases of tuberculosis in the United States, in California, in San Francisco all come from progression of aged infection that was dormant for many years,” said Priya Shete, MD, MPH, associate professor of medicine and epidemiology at UC San Francisco, in a statement reported by the Inter Press Service.
Active TB is an infectious disease spread through airborne droplets when individuals with the disease in their lungs cough, sneeze, or speak. Symptoms can include a cough lasting three weeks or more, unexplained weight loss, loss of appetite, and night sweats. Untreated active TB can be fatal. Latent TB, however, is a dormant infection where the bacteria are contained by the immune system and cannot be transmitted to others.
The Inter Press Service reported that Alemnew Dagnew, M.D., Head of Vaccines &. Biologics Development at the Gates Medical Research Institute, emphasized the disparity in risk perception. “Our risk of exposure should not depend on something as haphazard as where we are born,” Dagnew stated.
Current TB prevention relies heavily on the BCG vaccine, developed a century ago. While effective in protecting young children from severe forms of TB, its efficacy is limited in adolescents and adults, who are the primary drivers of transmission. Researchers are actively pursuing latest vaccine candidates, with several in late-phase clinical trials, offering a potential pathway to significantly reduce the global burden of TB.
Dagnew noted that a vaccine with 50% efficacy for protecting adolescents and adults could save 8.5 million lives, prevent 76 million new TB cases, and save $41.5 billion for TB-affected households over a 25-year period. However, equitable access to any new vaccine will be crucial to maximizing its impact.
The World Health Organization estimates that over a 25-year time span, a vaccine with 50% efficacy for protecting adolescents and adults could save 8.5 million lives, prevent 76 million new TB cases and save $41.5 billion for TB affected households.