Australian Researchers Launch Human Challenge Trial to Accelerate Strep A Vaccine Development
Key Insights
Australian researchers at Murdoch Children's Research Institute and Doherty Clinical Trials Limited (search) have launched a human challenge trial that deliberately infects healthy volunteers with Strep A (search) bacteria to accelerate vaccine development.
The trial follows successful development of a safe human challenge model and aims to enable faster testing of vaccine candidates against a pathogen that kills over 500,000 people globally each year.
Separately, University of Queensland (search) researchers in partnership with Moderna have demonstrated promising results using mRNA vaccine technology against Strep A (search) in mouse models, showing strong immune responses.
A groundbreaking human challenge trial has commenced in Melbourne, marking a pivotal advancement in the race to develop the world's first vaccine against Group A Streptococcus (search) (Strep A (search)). The trial, conducted through a collaboration between Murdoch Children's Research Institute (MCRI) and Doherty Clinical Trials Limited (search), will deliberately infect healthy adult volunteers with a specific strain of Strep A under controlled clinical conditions.
The innovative approach allows researchers to study infection progression in real time and develop models that could dramatically accelerate the testing of vaccine candidates compared to traditional trial methods. According to MCRI's Dr Josh Osowicki, "A Strep A (search) vaccine would not only prevent Strep A infections but also prevent invasive Strep A disease, which can be devastating for adults and children."
Global Health Impact Drives Urgent Research
Strep A (search) infections represent a massive global health burden, affecting approximately 750 million people annually and causing more than 500,000 deaths worldwide—exceeding the mortality rates of influenza, typhoid, or whooping cough. While most infections manifest as common sore throats, the bacteria can progress to cause scarlet fever (search), skin infections, and life-threatening conditions including toxic shock syndrome (search) and necrotising fasciitis (search).
The most severe consequences include post-infectious complications such as acute rheumatic fever (search), rheumatic heart disease (search), and kidney disease. Current treatment relies solely on antibiotics administered after infection occurs, with no preventive vaccine available despite the significant medical need.
mRNA Technology Shows Promise in Preclinical Studies
Complementing the human challenge trial efforts, researchers at the University of Queensland (search) have achieved encouraging results using mRNA vaccine technology against Strep A (search). The research, conducted in partnership with Moderna and published in Nature Communications, demonstrated efficacy and strong immune responses in mouse models.
Professor Mark Walker from UQ's Institute for Molecular Bioscience explained the rationale: "We know from the COVID-19 pandemic that mRNA technology is safe and clinically proven for viruses, so our team wanted to see if this technology could crossover and be used against bacterial pathogens. The results are certainly very encouraging."
The research team, led by Professor Gabrielle Belz from UQ's Frazer Institute, identified highly conserved components of Strep A (search) that were encoded in mRNA. "We were able to get good antibody responses with activation of several key immune cells, some of which go around and destroy pathogen-infected cells," Professor Belz noted.
Accelerated Development Timeline
The human challenge model developed by MCRI has been validated as safe and ready for testing vaccine candidates. Dr Andrew Brockway, CEO of Doherty Clinical Trials Limited (search), emphasized the significance: "Human challenge trials are an essential part of the global infectious disease toolkit, and the ability to conduct a study such as this positions Australia among a select group of countries capable of conducting these complex, high-impact studies."
Professor James McCarthy, Chief Medical Officer at Doherty Clinical Trials Limited (search), highlighted the facility's specialized capabilities: "Our facility was specifically designed so that we can safely conduct these important studies with a range of appropriate challenge models. Our staff are well trained to carefully expose participants to Strep A (search) under close medical oversight."
The University of Queensland (search) team projects their research could contribute to a commercial vaccine within at least three years. Professor Belz stated, "Our end goal is for our research to contribute to a commercial product that can be used on humans. That is at least 3 years away, but the project has extraordinary promise."
Targeting Vulnerable Populations
The development of a Strep A (search) vaccine holds particular significance for vulnerable populations, including children, elderly individuals, and Indigenous communities. Professor Walker noted that annually, 350,000 people globally die from rheumatic heart disease (search), while 150,000 deaths result from invasive Strep A infections.
The research initiatives represent a collaborative approach combining immunology and microbiology expertise with industry partnerships. The University of Queensland (search) project receives funding from the Leducq Foundation and an NHMRC grant, while the human challenge trial demonstrates Australia's growing capacity for conducting complex infectious disease research that could benefit global health outcomes.