QIMR researchers have just received a five year grant from the National Institutes of Health in the USA to develop a vaccine against group A streptococcus. This extremely prestigious grant makes QIMR one of the most successful recipients of NIH funding in Australia.
Group A streptococcus (GAS) is a serious human pathogen affecting people of all ages and all socio-economic levels. Infection with GAS can result in a variety of diseases including common streptococcal pharyngitis (throat infection), particularly common in children, and the far more serious pneumonia and toxic shock-like syndrome, primarily affecting older individuals. Repeated infections with GAS can result in rheumatic fever (RF), rheumatic heart disease (RHD) and acute-glomerulonephritis (serious kidney illness). RHD which is autoimmune in nature is of most concern as it can lead to heart failure and a significantly shortened lifespan. The disease is confined largely to developing countries where over-crowding and poor access to health care are contributing factors.
Australia’s Aboriginal population experiences the highest rate of the disease in the world, with the incidence of RF being as high as 651 per 100,000 per year, and the prevalence of RHD being as high as 3,000 per 1,000,000. The average age of onset of RF in Aboriginal children is 11 years and the mean life expectancy of Indigenous people with RHD is 33 years.
Since RF only ever follows infection with group A streptococci, a practical strategy to prevent the disease is to prevent streptococcal infection – which is what QIMR is aiming to do through the development of an effective vaccine. Presently, there is no strategy for primary prevention that is proven to work in less-developed countries, so a vaccine is clearly needed. QIMR’s long-term goal is the development of broad-spectrum global vaccine that prevents GAS infection and its associated diseases, including rheumatic fever. The GAS vaccine candidate identified by QIMR is based on a peptide antigen from the conserved region of the M-protein.
More importantly, QIMR has four potential vaccine constructs that use this antigen, each of which has shown good immunogenicity, safety and protection in pre-clinical studies. At the conclusion of this project, scientists expect to have completed an initial Phase 1 trial in adult volunteers in Australia and a larger multi-centre Phase 1 trial in Australia and in a developing country. They will then further develop a vaccine that can be delivered intranasally making administration simple.