New study questions the effectiveness of a TB vaccine

A new clinical study calls into question the use of a new tuberculosis vaccine for national vaccination programs. The vaccine MVA85A was found to be less effective in treating TB when compared alongside vaccinations for other diseases.

From Reuters Alert Net, writer Kate Kelland unpacks the study for us.

Martin Ota of the Medical Research Council Laboratories in Banjul, Gambia, who led the study, said the data should help doctors work out the best way to integrate the MVA85A into infant immunisation programmes in the future.

"We have a real opportunity to make sure that children are protected ... against tuberculosis by introducing effective and well-timed immunisation programmes," he said in a statement about the study. "This can only be achieved with robust information gathered from well-conducted clinical trials."

Standard childhood vaccinations are routinely given in developing countries as part of a plan known as the Expanded Programme on Immunisation (EPI).

It includes vaccines for diphtheria, tetanus and whooping cough, as well as the current vaccine for TB, Bacille Calmette-Guerin (BCG). The plan helps boost vaccine coverage by cutting the need for repeated visits to health clinics, which are often difficult to get to in poor, rural areas.

Although BCG protects against severe forms of TB in childhood, increasing rates of the disease in adults suggest its effect is not long-lasting.

TB is currently a worldwide pandemic that kills around 1.7 million people a year. The infection is caused by the bacterium Mycobacterium tuberculosis and destroys patients' lung tissue, causing them to cough up the bacteria, which then spread through the air and can be inhaled by others.