The current tuberculosis vaccine--bacille Calmette-Guérin (BCG)--has produced varying efficacy rates worldwide, ranging from 0% to 80%. In a new study published in Nature Medicine, however, researchers have found a promising lead for a new TB vaccine based on a related bacterium.
Mycobacterium smegmatis is in the same bacteria family as TB. Albert Einstein College of Medicine's William Jacobs and his colleagues adapted the bacterium by adding the TB's esx-3 genes to it, creating a new strain called Ikeplus. Mice treated with Ikeplus lived twice as long as those injected with the BCG vaccine on average--135 days versus 65 days.
"This is something we've dreamed about for years, to be able to get longer protection and bactericidal immunity," Jacobs said, according to the BBC. "Ikeplus is different from any other TB vaccine and it's a new tool for the TB arsenal."
Researchers don't know if the vaccine will lead to a more effective human version, and Jacobs expects to continue researching Ikeplus to achieve higher long-term survival rates. In the current study, long-term surviving mice--who lived more than 200 days--only accounted for 20% of the total.