About 1.7 million people die from tuberculosis (TB) annually; 500 children die of it every day. As such, new tools to control TB are urgently needed.

Dr Helen McShane of the University of Oxford has been developing and testing a 'prime–boost' vaccine for TB. The existing vaccine, BCG, is not always fully protective against TB disease, particularly in adults. However, it may be more effective when used as a 'prime' in combination with a second 'boost' immunisation based on the new vaccine.

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The combination has been shown to be safe and immunogenic in phase I and phase II clinical trials in adults. With recently agreed Technology Transfer funding, further phase II trials, first in adults then in children and infants, are planned for South Africa's Western Cape – where TB is rife.

Professor Ajit Lalvani, whose Senior Research Fellowship in Clinical Science was renewed this year, has identified another possible benefit of BCG. BCG has been thought to work by preventing TB disease rather than by blocking initial infection. Use of a new diagnostic test by Professor Lalvani showed that BCG did seem to protect children from infection as well as disease. BCG may therefore be more useful in disease control than once thought.

Sadly, advanced TB diagnostics are not an option for resource-poor countries, while the low-cost methods promoted by the WHO lack sensitivity and give no information about drug resistance. But a new test, the MODS assay (microscopic observation drug susceptibility), developed in Peru by Professor Bob Gilman and evaluated and refined by Dr David Moore and colleagues at Imperial College London and in Lima, Peru, is an affordable, sensitive and rapid test for TB and drug-resistant TB. The speed can save lives – a patient with multidrug-resistant TB may be dead before drug resistance has been identified by conventional methods.

External links

• McShane H et al. Recombinant modified vaccinia virus Ankara expressing antigen 85A boosts BCG-primed and naturally acquired antimycobacterial immunity in humans. Nat Med 2004;10(11):1240–4.
• Soysal A et al. Effect of BCG vaccination on risk of Mycobacterium tuberculosis infection in children with household tuberculosis contact: a prospective community-based study. Lancet 2005;366(9495):1443–51.
• Moore DA et al. Microscopic-observation drug-susceptibility assay for the diagnosis of TB. N Engl J Med 2006;355(15):1539–50.