New TB vaccine could save over a million lives

Jul 31 2007

Initial trials of a new tuberculosis (TB) vaccine mean the drug will now progress to phase II trials.

This latest tool in the fight against TB is the first vaccine to be produced in 80 years.

Following successful safety tests of the MVA85A vaccine carried out on healthy adult volunteers in The Gambia, a phase II clinical trial began last week on infants there.

The phase II trials will also take place in South Africa, where one in every 100 has TB.

The vaccine which was developed by a team at Oxford University, England, will be given to adolescents and HIV-infected adults.

The rising infection rates along with the emergence of drug resistant strains of TB, means a new and effective vaccine is urgently needed.

Tuberculosis causes a fever, a persistent cough that may be bloody, fatigue and weight loss, and still kills two million people worldwide each year, 98 per cent of them in developing countries.

The current vaccine in use, Bacille Calmette-Guerin (BCG), only provides protection against severe forms of tuberculosis, but that effect appears to wear off in adolescence which is why in the UK the BCG vaccine is usually given at age 13.

Experts say BCG is not safe for use in people with AIDS, and also may not be safe for use in HIV positive people because it is a live vaccine that can cause disease in people with weak immune systems.

The new MVA85A vaccine is intended as a booster for BCG and is used alongside BCG using a protein from the bacteria that causes TB - Mycobacterium tuberculosis - to activate immune cells called T cells, and boost the body's immune response.

Patients receiving the booster have been shown to produce up to 30 times the normal level of "helper" T cells which act as "conductors" orchestrating the immune response.

The vaccine was developed by the Wellcome Trust, an independent charity which funds research into improving human and animal health.

The trust says data from HIV negative adults and adolescents in South Africa indicates that the vaccine is safe and generates very strong immune responses.

The researchers will study data from 471 HIV-negative four-month-old babies to determine the level of immune response it triggers at particular dosing levels and how it interacts with other vaccinations, such as those for diphtheria, pertussis (whooping cough), tetanus and Haemophilus influenzae type b (HIB), which causes pneumonia and meningitis.

Experts in South Africa say both HIV and TB are diseases of poverty in the country and one makes the other worse.

They say a new vaccine is needed to eliminate the disease and over a million lives a year could be saved with an effective vaccine.