New TB vaccine could protect before and after exposure

A new tuberculosis vaccine developed by a team of scientists at the Statens Serum Institute in Copenhagen may be able to offer protection both before and after exposure to the tuberculosis causing Mycobacterium tuberculosis bacteria.

Current vaccines like the BCG vaccine will only work effectively if they are given to a person before they have been exposed to the bacterium. In some areas that have a majority of already infected population like Cape Town, South Africa, these vaccines would not be effective, the BBC reports.

In addition, the bacterium can exist in both latent and active forms. In its latent form, TB is essentially immune to the current vaccines.

The new TB vaccine combines proteins in such a way as to trigger an immune response to both active and latent forms of TB, according to the BBC.

"A vaccine which can both protect against initial infection and protect from a breakdown of infection into disease is a major breakthrough," Professor Peter Davies, secretary of the group TB Alert, said, according to the BBC. "One of the main disadvantages of BCG was that it could only prevent infection going on to disease in the initially uninfected individual. It was therefore of no use in protecting infected adults who would become an infectious source of disease. Protecting children, though of value, does not protect against transmission, as children with active disease do not usually transmit disease.

The new vaccine has thus far been successful in animal trials and the research has been featured in the journal Nature Medicine.