Researchers attempt to overcome issues to develop effective TB vaccine in South Africa

While scientists have made progress to advance the development pipeline for a new tuberculosis vaccine in South Africa, more advances has been stalled by several gaps and challenges.

Several issues researchers face include a lack of understanding of the parts of a protective immune response, a limited capacity of the infrastructure of clinical trials and a lack of pre-determined future pathways to facilitate licensure of the vaccines.

Roxana Rustomjee, a researcher with Emergent BioSolutions, and other scientists met on the subject of tuberculosis in South Africa and determined potential solutions to the issues facing a new TB vaccine, the journal Tuberculosis reports.

The researchers determined that TB vaccine trials must include age-specific data because adolescents are at high risk for the disease due to their immune systems and can be easily targeted by vaccination campaigns.

"While TB disease rates are lower in this adolescent age group, they are an ideal group to target for a TB vaccination boost before the sharp rise in disease incidence seen in young adult populations," the researchers said, according to the journal Tuberculosis. "Further, adolescents are an attractive target group as they may be more easily reached through the school system in vaccination programs and thus ultimately drive good vaccine coverage should an effective boost vaccine for the prevention of TB become available."

TB vaccine trials have also been challenged by the lack of availability of advanced trial sites. The researchers found that without such trial sites, vaccine candidates will be unable to enter advanced clinical trials.

"Over the last 15 years, the importance of developing infrastructure for TB vaccine trials in high incidence countries has been more clearly recognized," the researchers said, the journal Tuberculosis reports. "South Africa has led the way in building this infrastructure with funding support from Aeras, European Developing Countries Clinical Trial Partnership, European Commission and National Institute of Health, but unless further investment is made, and more sites are developed, the progress of many promising vaccine candidates may be stalled. Criteria need to be developed for site selection and to facilitate site development."

To effectively create candidates for new TB vaccines, the researchers said that validated animal models to predict efficacy must be created, case definitions used for TB must be validated and standardized across trials, adaptive trial designs should be adopted, cooperative regulatory strategies should be created to offer solutions to licensure hurdles and economic forecasts must be made to guide policy and implementation strategies.

By addressing TB vaccine issues, the researchers hope to improve the effectiveness in developing new TB vaccines.

"The anticipated outcome is therefore to build awareness of the issues and to start increasing efficiencies in planning and implementing strategies for late stage clinical development of TB vaccines," the researchers said, according to the journal Tuberculosis.