Scientists reveal new TB vaccine blueprint
Tuberculosis (TB) researchers on Tuesday revealed a new strategy to guide the development of a vaccine, which many now believe may be the world’s best hope for beating TB.
The TB vaccine blueprint, which was published in a special issue of the journal Tuberculosis this month, recommends an intensified international effort to develop TB vaccines.
Mike Brennan, senior advisor for Global Affairs at Aeras, a non-profit organisation dedicated to developing a TB vaccine, said the blueprint would be a “rallying point for moving in a new direction in vaccines in the next decade and hopefully help to cure one of the deadliest diseases”.
Despite the existence of effective treatment and a vaccine that protects against severe forms of TB in children, nine million new cases of TB occur each year and there are more than 1.4-million deaths from the disease annually. This means the development of an effective vaccine is seen as critical to reducing the global burden of the disease.
Brennan said that in addition to improving carrying out further research and clinical trials, there is also a critical need for advocacy, community acceptance and funding of vaccine trials.
“Resource mobilisation is one of our biggest issues,” he said.
According to Brennan, large vaccine trials could cost as much as $200-million per vaccine but only about R78-million is contributed to the effort each year.
The need for a TB vaccine has grown more important as drug resistant strains of the disease continue to thrive. In South Africa, which has one of the highest incidences of TB in the world, local scientists have begun to play an increasing role in vaccine research.
There are currently five TB vaccine trials underway in the country. Dr Hassan Mahomed, academic team leader at the South African TB Vaccine Initiative is the principal investigator on three of those trials, including one which involves the leading candidate vaccine, MVA85A.
The MVA85A trial is being conducted in the Western Cape and will assess the effectiveness of the vaccine on infants. The results will be available early next year. Researchers hope that the vaccine, to be given three or four months after birth, will boost the resistance of children in developing countries against TB.
Mahomed said local researchers were making history in TB development. “For the first time we will have efficacy results, [and see] whether this trial prevents TB,” he said.
He added that South Africa was well positioned to carry out trials for a TB vaccine precisely because of the huge burden of TB in the country but also because of its skilled scientists, good infrastructure and capable regulatory authorities, who are well placed to oversee trials and evaluate their results.
Vaccines should target healthy people
Mahomed said that the latest thinking on vaccines is moving towards the position that a TB vaccine should target healthy people, who are not HIV positive, as this should have a greater effect on preventing the spread of the disease.
Although there are currently no trials in South Africa that focus on this group but plans are underway to initiate such a study by early 2013.
Dr Gavin Churchyard, chief executive of independent TB research organisation, Aurum Institute, said the world’s best hope for eliminating TB as a global threat is to find an effective vaccine.
The Aurum Institute recently released the results of a large TB drug trial, which took a radical approach to reducing TB infections in the high transmission setting of South African gold mines. In the Thibela study, researchers provided treatment to healthy miners in an attempt to prevent them from contracting the disease. Although promising at the outset, the trial failed to control TB in the mines even though it reduced TB risk in individuals who were taking the drug.
Churchyard said that the results of the Thibela trial had highlighted the need for new tools such as a vaccine to improve TB control in resource-poor settings with high rates of TB.
Data from the World Health Organisation, which aims to eliminate TB by 2050, also suggests that this would only be possible if a vaccine that is at least 50% effective is available.
In a statement released on Tuesday Health Minister Aaron Motsoaledi said that the blueprint provides an opportunity to coordinate efforts to halt the spread of the disease.
“In our country alone, a vaccine could save hundreds of thousands of lives each year and could be instrumental in ultimately eliminating tuberculosis as a public health emergency,” he said.
South Africa’s national strategic plan to combat HIV and TB has set the ambitious goal of halving TB infections and deaths by 2016.