Oct. 31 (UPI) -- Tuberculosis kills an estimated 1.5 million people annually around the world.
The latest results from an ongoing clinical trial involving a new vaccine suggest the shot, which is administered in two doses, may help limit the spread of the deadly and difficult-to-treat disease. The findings were published this week in the New England Journal of Medicine.
"It could save more than 600,000 lives per year," said Joel Ernst, professor and chief of medicine at the biomedical sciences graduate program at the University of California-San Francisco, who specializes in TB research but was not involved in the current study.
The vaccine, manufactured by drugmaker GlaxoSmithKline, is called M72/AS01E, and it was shown to be effective at preventing progression to pulmonary TB in more than half of the participants in the Phase 2b clinical trial in preliminary results published last year.
The new data, which summarizes patient outcomes three years after receipt of both doses of the vaccine, indicates that just 13 out of the more than 1,600 people with latent Mycobacterium TB who received the two shots ultimately developed pulmonary TB three years later, the more lethal form of the disease.
As much as one-quarter of the world population is infected with latent, or non-active, Mycobacterium TB, but only 10 million people annually progress to pulmonary TB. Of these, roughly 500,000 are diagnosed with drug-resistant forms of the infection, according to the World Health Organization.
"This is an important step" in the fight against TB, Ernst told UPI. "Taken collectively, the results indicate it really is possible to make a TB vaccine that works."
Although the numbers of people diagnosed with TB continue to decline in countries like the United States, which reported just over 9,000 cases in 2018, according to the Centers for Disease Control and Prevention, the disease remains a significant cause of death in parts of Asia and Africa.
GSK has reportedly been working on the vaccine for more than two decades, and the preliminary results published last year suggested that it is effective at preventing progression to pulmonary TB in more than half of those who receive both doses.
This may not seem significant, Ernst acknowledged, but it is enough to show that protecting against TB is possible.
More analyses should help determine why the vaccine didn't protect everyone, he said."That will tell us what needs to be done to modify this vaccine or make another vaccine that better protects people against TB."
M72/AS01E is likely several years from widespread use. However, Ernst believes the vaccine should be available well before 2030, the year by which the WHO hopes to put an end to the worldwide TB epidemic. Phase 3 clinical trials, the next step for the vaccine's development, are in their early stages.