Tuberculosis vaccine research: progress is being made

7 Jun 2010

Babs Verblackt, Citizen News Service

Source: TropIKA.net

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The development of new vaccines against tuberculosis is progressing but many issues remain to be further researched, according to European scientists attending a symposium held in Zaragoza, Spain, 3–4 June. The international meeting, ‘Research and development of new tuberculosis vaccines’, was organized by the Tuberculosis Vaccination Initiative.

TB is of growing concern worldwide and the only currently available vaccine, BCG, has limited efficacy in adults and there are safety issues in HIV-infected newborns.

“I don’t need to remind people here of the state of the problem,” said Dr Ann Rawkins of the Centre for Emergency Preparedness and Response of the UK’s Health Protection Agency, referring to the two million TB deaths and nine million new TB cases worldwide per year. “The international goal of elimination of the disease by 2050 cannot be reached unless we get new diagnostic tests, new drugs and new vaccines. A large number of new vaccine candidates are currently at various stages of development.”

Research into new TB vaccines either aims to replace BCG or to boost the immunity it gives. Professor of Immunology Hazel Dockrell, of the London School of Hygiene & Tropical Medicine, stressed the need to determine exactly what the BCG vaccine is doing. “BCG has been around for a very long time – it was first given to a child in 1921 – it is surprising we don’t know more about it,” she said. “We need to understand what sort of immunity BCG gives and what features of BCG should be improved.”

Research done by Dockrell and colleagues found that young adults and infants in the UK and Malawi gave different immune responses to BCG vaccination. “That matters because many new vaccines now in development are boosting vaccines, aiming to improve BCG. But will they work better than BCG in areas where BCG itself doesn’t induce good protection?”

Professor Paul-Henri Lambert from the University of Geneva stressed the importance of safety issues for new TB vaccines. “Rare adverse events can kill newly developed vaccines. A theoretical risk of safety issues has often hampered the development of a new vaccine. And unjustified allegations can lead to limiting use of a good vaccine,” he said.

Professor Douglas Young, Fleming Professor of Medical Microbiology at Imperial College, London highlighted the importance of more diversity in TB vaccine research. Most vaccines currently in development focus on boosting the body’s natural immune response. “But it might as well be that the vaccines we’re making at the moment are exactly the vaccines TB wants us to make,” Young warned.

“TB might be perfectly happy with the way the natural immune response works, getting enough opportunities to transmit,” he said, elaborating on the global diversity of TB strains and how these strains orchestrate the body’s immune reaction. While current research is centred around cell-mediated immunity, “There is a landscape of diversity which is not yet exploited” Young said, encouraging his fellow scientists not to neglect the immense variety of immune response.

About TBVI

The Tuberculosis Vaccine Initiative (TBVI) is an independent non-profit organization that stimulates and coordinates the development of new, globally accessible and affordable vaccines against TB. Further information is available here.

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28 Jun 2010 by Paul Chinnock:

A report on further developments at this conference is available on the TropIKA.net blog: http://blog.tropika.net/tropika/2010/06/09/research-and-development-of-new-tuberculosis-vaccines-conference-update/