Researchers have developed a vaccine that can fight off tuberculosis infection both before and after exposure to the disease-causing bacterium. The vaccine, so far tested only in mice, was reported online yesterday in Nature Medicine.

“A vaccine which can both protect against initial infection and protect from a breakdown of infection into disease is a major breakthrough,” Peter Davies, secretary of the group TB Alert who was not involved in the research, told the BBC.

A team led by Peter Andersen from the Statens Serum Institut in Copenhagen, Denmark developed the experimental vaccine by combining two antigens expressed by Mycobacterium tuberculosis early during infection together with an antigen found only during persistent or latent infection. In experiments with mice, the researchers showed that the dual-action vaccine blocked the pathogen from taking hold after first exposure as well as prevented the bacteria from reactivating after lying dormant in the cell.

“The paper shows that it’s possible to target a vaccine also to antigens that are preferentially upregulated as bacteria adapt to long-term persistence and thereby change their antigenic compositions,” Andersen told Nature Medicine. “And by targeting these it is possible to prevent reactivation.”