Johns Hopkins Nasal Spray Vaccine Effective in Preventing TB Relapse

Tuberculosis (TB) remains one of the world’s largest global health crises. Although antibiotic treatment is available, many patients experience relapse due to bacteria that are able to ‘hide’ and become resistant to standard therapy. Addressing this challenge, a research team from Johns Hopkins Medicine and the Johns Hopkins Bloomberg School of Public Health has developed a new medical innovation. They have created an experimental therapeutic DNA vaccine for TB that is administered via the nose (intranasal). This spray vaccine is specifically designed to strengthen the body’s immune system in tracking down and destroying drug-tolerant TB bacteria, often referred to as ‘persister’ bacteria. These persister bacteria have long been the culprit, capable of surviving in the body despite patients undergoing long-term antibiotic treatment, later triggering active disease again. In laboratory trials on animal models (mice), this therapeutic DNA vaccine showed highly promising results. When administered alongside a first-line drug regimen, the vaccine accelerated stable bacterial clearance, reduced inflammation in the lungs, and prevented post-treatment relapse. Furthermore, the vaccine proved capable of enhancing the effectiveness of drugs used to combat multidrug-resistant TB. Biologically, the vaccine works by combining the TB stringent response gene (relMtb) with a gene encoding a dendritic cell-targeting chemokine called Mip3? (or CCL20). This unique combination generates a strong signal within the respiratory tract that attracts immature dendritic cells, key immune cells that capture TB proteins and ‘introduce’ them to T cells to coordinate a targeted attack. Testing was subsequently extended to non-human primates (rhesus macaques), the gold standard for preclinical TB vaccine evaluation. The results showed that the nasal spray vaccine successfully triggered a measurable TB-specific immune response, both in the bloodstream and in the airways (lungs), which persisted for at least six months. This innovation aligns with the World Health Organisation’s call for the development of new therapeutic vaccines to complement existing antibiotic treatments. Such vaccines are expected to shorten the notoriously long and exhausting TB treatment duration, while also curbing the spread of drug-resistant TB variants.