According to the World Health Organization (WHO), 1.7 million people died of tuberculosis (TB) in 2016, but even so we still do not have a vaccine that provides full protection against TB. For this reason, researchers are trying frantically to improve vaccination strategies with regard to this disease. And their research is gaining momentum.
Forty-two research centres collaborate under the umbrella of the EU-subsidised TBVAC2020 programme. Universities and the pharmaceutical companies with which they have entered into partnerships, both from the EU and from elsewhere, are seeking to identify the most promising potential vaccines. As a result, twenty-five potential vaccines are now in early development, and thirteen are being tested for safety and efficacy in hospitals. This constitutes major progress, considering that fifteen years ago, we hardly had any potential vaccines.
The predictive power of macaques
BPRC is one of the organisations taking part in the TBVAC2020 partnership. Macaques may play a vital part in our studies focusing on the prevention and treatment of TB. These non-human primates are very similar to humans in many regards, e.g. in terms of hereditary kinship, immune system, susceptibility to tuberculosis and the way in which the disease presents.
For this reason, macaques have greater predictive power for humans than any other animal model available. In addition, the controlled conditions of a laboratory setting are particularly suited to evaluating new concepts and studying pathomechanisms and the protection afforded by vaccination.
One of the most promising potential vaccines is MTBVAC, a variant of the pathogen whose strength has been diluted by means of genetic modification. This vaccine was developed by researchers at the University of Zaragoza and their colleagues. An early precursor to MTBVAC was previously tested in a pre-clinical primate study, with encouraging results, as part of a comparable EU-subsidised partnership led by the TuBerculosis Vaccine Initiative (TBVI) in Lelystad. The BPRC-affiliated researchers involved in that partnership showed at the time that this potential vaccine reduced TB symptoms in rhesus macaques.ref By now this vaccine is being tested in hospitals, and it appears to be safe and provoke the right immune responses in humans, too.
Mode of administration matters, too
In addition to the vaccine itself, the manner/route of administration may affect the level of protection given by the vaccine. For this reason, the TBVAC2020 partnership is also conducting research on innovative routes of administration. For instance, BPRC is investigating the question as to whether topical administration of the vaccine to the lungs – the organ where tuberculosis bacteria reside – can enhance the level of protection against the disease. So far, the results have been promising.
The researchers hope that the unprecedented joining of forces in this large-scale partnership will eventually result in a more effective therapy against TB and that the number of people suffering and dying from this disease will be reduced.
Wish to find out more about this study? Read this article.
Ref: Verreck et al, PLoS One, 2009
MVA.85A boosting of BCG and an attenuated, phoP deficient M. tuberculosis vaccine both show protective efficacy against tuberculosis in rhesus macaques.