Tuberculosis (TB) is caused by the bacillus
Mycobacterium tuberculosis and is one of the leading causes
of all adult deaths worldwide, as well as the leading cause of death
in HIV-positive people.
An estimated 1.5 million people die of TB each
year. Not all infected persons develop active disease, but the risk
of becoming sick is increased when the immune system is weakened,
for example by HIV infection.
Effective and affordable medicines to treat
TB disease have been available for decades but these must be taken
for six to eight months and, if treatment is not completed, the
emergence of drug-resistant strains of the bacillus may be encouraged.
According to WHO, only 15 per
cent of people with TB disease worldwide are currently receiving
the recommended form of treatment known as DOTS (directly-observed
Multidrug-resistant strains of TB are of increasing
public health concern worldwide. The existing vaccine against
tuberculosis, BCG or Bacille Calmette-Guérin, is almost 80 years
old. It is effective in infants for preventing some highly dangerous
forms of the disease (miliary TB and meningitis) and is widely
given to babies through the WHOs Expanded Programme on Immunization.
However, additional vaccines are needed to combat this major killer.
For further information see
More vaccines for which research is needed