Step forward in fight to eliminate tuberculosis

Professor Philip Hill was involved in the research, published today in the world-leading New England Journal of Medicine, which evaluated the effectiveness of a new way to prevent people with latent tuberculosis infection developing the full-blown disease.

Results show a four-month daily regimen of antibiotic rifampicin in both adults and children is as effective as a nine-month daily regimen of another antibiotic, isoniazid.

"Not only was it as effective at preventing tuberculosis, but the participants were more likely to complete the course and had fewer side effects," Professor Hill explains.

"This is a real step forward in our aspiration to eliminate tuberculosis. It means we can now offer a more attractive option to the many millions of people in the world who are at risk of developing tuberculosis."

Tuberculosis is a major global health problem. It is estimated a quarter of the world's population are infected with the pathogen that causes tuberculosis and very few of them are offered preventive treatment to stop them developing the disease.

"Importantly, we know that if we don't find a way to give them preventive treatment, we will never eliminate tuberculosis from the planet," Professor Hill says.

Led by Professor Dick Menzies from McGill University in Canada, the study recruited individuals in Canada, Indonesia, Guinea, Benin, Brazil, Australia, Korea, Saudi Arabia and Ghana. Professor Hill's group worked with collaborators in Bandung, West Java, Indonesia to enrol and follow-up 1000 of the 6900 participants across the study.

Professor Hill explains that most people who are infected after exposure to tuberculosis do not develop the disease, the mycobacterium stays "asleep" in their system. The risk can be brought down to close to zero if they have preventive treatment.

Traditionally, this has involved nine months of daily isoniazid, but the long duration of treatment and the side effects, including the potential to develop hepatitis, are major drawbacks.

While the results of the present study may not impact on the large part of the world's population who are not offered preventive treatment, Professor Hill considers this may not be the case if researchers can discover an even shorter treatment regimen.

"One option already envisaged is higher dose rifampicin, which is now used safely for tuberculosis meningitis and is being evaluated in the treatment of tuberculosis of the lungs. Preventive treatment using high dose rifampicin for four to six weeks is an obvious option to consider next."

In anticipation of the increasing importance of combating latent tuberculosis infection for the elimination of tuberculosis, Professor Hill and others have made this area a major focus of their research, conducting a wide range of studies with collaborators in different parts of the world.

It is hoped that some of this work will be done in New Zealand where, for example, M?ori are likely to have a relatively high rate of latent tuberculosis infection. Although New Zealand has a low rate of the disease, new cases continue to occur with half of New Zealand-born tuberculosis patients being M?ori.

Earlier this year Professor Hill received a $250,000 grant from the Health Research Council to further investigate tuberculosis among M?ori in New Zealand.