Towards a Strep A vaccine

New research from Griffith University’s Institute for Glycomics, Queensland, has advanced the development of a vaccine for the bacteria Streptococcus A.

Diseases promoted by Strep A infection kill more than 500,000 people globally per year. In Australia, First Nations peoples bear an unequal share of deaths related to Strep A disease.

“There is currently no vaccine available as immunity to Strep A in humans takes years to develop,” says lead researcher Manisha Pandey. “This is because it is highly virulent and subverts innate and acquired immunity.”

Working with collaborators at Statens Serum Institut, Denmark, the Griffith researchers identified two Strep A proteins that induce longer immunity in the host, and combined them with an adjuvant, which provokes a stronger immune response.

Pandey says that this vaccine-technology platform has been tested in human clinical trials for other vaccines and its safety and efficacy is established.

In a preclinical study on mice, two intramuscular injections followed by an intranasal vaccine induced the production of antibodies that protected the throat and skin from Strep A. There were further tests on rats for toxicological assessment of the vaccine.

“The inequitable burden of Strep A disease in the Indigenous population of Australia has been one of the major driving forces for this research,” says Pandey.

“Acute rheumatic fever and rheumatic heart disease (RHD) are the most severe and life-threatening consequences of Strep A infection. The mortality rates in Indigenous populations due to RHD are reported to be the highest in the world.”

Pandey adds that the risk factors for the high rate of Strep A infection in Indigenous communities relate to poverty, poor environment conditions, household overcrowding and limited access to medical care.

Institute for Glycomics professor Michael Good says that a Strep A vaccine “would have a transformative effect on the health of remote Indigenous communities”.

The candidate vaccine can now proceed to clinical trials but there’s no immediate prospect of relief for Indigenous Australians.

“It will be at least another 5–10 years before an approved vaccine might be available,” says Pandey. “One of the significant barriers is funding. Clinical trials are very expensive to run and [appropriate] resourcing of adequate funds is often quite inhibitory to progress.”

The research is published in mBio.

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