Novas vacinas para tuberculose.

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Novel tuberculosis vaccines on the horizon
Shreemanta K Parida and Stefan HE Kaufmann
Eleven new tuberculosis (TB) vaccines are in various phases of clinical trials. These include subunit vaccines to improve the current vaccine BCG, and recombinant BCG to substitute for BCG, both given pre-exposure to prevent active disease. A plethora of potential candidates have reached various stages of the pre-clinical development pipeline, some ready to enter Phase I clinical trial soon. A boost vaccine to top up the immunity of existing BCG is on the horizon and will have to suffice until a better candidate to replace BCG is ready. The live mutants of Mycobacterium tuberculosis show great promise, but face a myriad of regulatory challenges.

competent. Once the immune response becomes compromised, TB disease is reactivated.

Epidemiology
One person dies of TB every 18 s, almost 2 million annually and someone develops active TB every 4 s, amounting to more than 9 million new cases each year [1]. Up to one third of the world’s population is estimated to harbor the causative agent Mtb in its dormant form. These latent TB-infected (LTBI) subjects are at risk of developing active TB disease owing to immune exhaustion/suppression or deficiency, for example during coinfection with HIV. In fact, the HIV/AIDS pandemic has become the driving force of the resurgence of TB. The threat has been confounded by multidrug-resistant and extensively drug-resistant TB (MDR-TB and XDR-TB) [2,3].

Address Max Planck Institute for Infection Biology, Department of Immunology, ´ Chariteplatz 1, D-10117 Berlin, Germany Corresponding authors: Parida, Shreemanta K ([e-mail]) and Kaufmann, Stefan HE ([e-mail])

Current vaccine
The current vaccine for TB, BCG, has been administered to more than 4 billion subjects, so far. It has proven relatively safe and protective against severe forms of childhood TB, but fails