Grant: CIHR Fellowship

Streptococcus pneumoniae, also called the pneumococcus, asymptomatically colonizes the nasopharynx of young children. However, the pneumococcus can eventually spread to the lungs and cause a life-threatening respiratory illness called pneumonia, which is a major killer of young children in developing countries. Vaccination is the best strategy to fight the disease by preventing initial bacterial colonization. Two pneumococcal vaccines are currently available; however, both rely on a single bacterial component called the capsule. Several drawbacks are associated with capsule-based vaccines. Notably, they do not prevent pneumococcal colonization of the nasopharynx and do not provide universal protection. In addition, they are difficult and costly to manufacture. An improved vaccine is therefore greatly needed. We developed a novel vaccine that has the potential to circumvent these limitations by using live but weakened pneumococci. However, before such a vaccine could be clinically tested, we need to 1) determine its impact on the immune system, 2) determine which bacterial components are important for establishing protection, and 3) determine if antibiotic treatment in conjunction can alter the efficacy of the vaccine. The reservoir for pneumococci is the nasopharynx of asymptomatic humans. We therefore believe that blocking colonization in the first place would reduce its overall dissemination in the population. It would also prevent the development of pneumococcal-related diseases. Our vaccine has the potential to provide such protection. Its development and eventual implementation could reduce the global burden and also reduce morbidity and mortality associated with pneumococcal infections. Preventing pneumococcal carriage would also alleviate treatment-associated medical costs. In conclusion, development of an improved pneumococcal vaccine would be highly beneficial for the global population, both in the developed and the developing countries.