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Murdoch Children’s Research Institute launches an international trial of a 21-valent pneumococcal vaccine to protect babies against pneumonia, meningitis, and sepsis

The Murdoch Children’s Research Institute has launched an international trial of a new 21-strain pneumococcal vaccine for babies, a world-first trial in infants. This study aims to see if the vaccine can safely provide broader protection against serious infections like pneumonia, meningitis, and sepsis. By protecting infants against more types of pneumococcal bacteria than current vaccines, researchers hope this trial could help keep babies healthier and prevent life-threatening illnesses worldwide.

Pneumococcal vaccine: protecting infants from serious infections

Infants are currently administered the 13-valent pneumococcal conjugate vaccine, commonly referred to as PCV13. This vaccine is designed to protect against 13 specific strains of pneumococcal bacteria, which are known to cause severe diseases such as sepsis and meningitis, among others. Pneumococcal infections can lead to serious health complications, particularly in young children, making vaccination a vital part of preventive healthcare.

PCV13 is included in the standard childhood immunisation schedule in many countries, including the United Kingdom. It is typically given to infants at 16 weeks of age, following an initial dose at 8 weeks and a booster at 12 months. This vaccination strategy helps ensure that children develop a strong immune defense against these strains early in life, ultimately reducing the incidence of pneumococcal disease in the population. Regular immunisation not only protects individual children but also contributes to the overall health and safety of the community by lowering the spread of these harmful bacteria.

A new 21-strain standard for pneumococcal protection

The new 21-strain pneumococcal vaccine could more broadly protect children from severe disease by expanding the number of strains it targets. The trial will involve a pneumococcal vaccine given as a four-dose regimen (given at two, four, and six months of age and a booster dose at 12-15 months). All other vaccines on the National Immunisation Program will be given alongside the pneumococcal vaccine. 

Participants must be:

• Aged two months at study entry (42 to 89 days old);
• Healthy;
• Full-term birth and birth weight over 2.5kg;

Participants must meet specific health criteria to ensure their safety and well-being throughout the trial. This includes being born after a gestation period of 28 to 36 weeks with a birth weight of 1.5 kg or greater, and being assessed as medically stable.

MCRI Professor Margie Danchin said having a vaccine that could offer broader protection was crucial to protecting more children from severe preventable infections and death.

“Pneumococcal infections are caused by a common bacterium that lives in the nose and throat and can lead to serious complications such as pneumonia and severe infections of the bloodstream and lining of the brain,” she said.

“There are more than 90 different strains of the pneumococcal bacteria, and no vaccine is able to protect against every strain. But our trial of this new pneumococcal vaccine, which has shown promising results in earlier studies and will protect against 21 strains, has the potential to save more lives.

“We always need to ensure that children and families are being offered the best protection against severe disease with new and improved vaccines. However, we need to demonstrate that they are safe and can trigger a protective antibody response in young children before they can be introduced into the national immunisation schedule.”

Lisa, whose daughter Lucy, 3 months, is taking part in the trial, said she welcomed the opportunity to play a part in finding a more effective pneumococcal vaccine.

“Being a nurse, I know how super important vaccination is to keeping my baby safe,” she said. As a parent of a young baby, especially in the winter months, you want as much protection as possible. Without trials like this, we wouldn’t discover better, more effective vaccines. Research is what helps to safeguard our children for the future.”

Autism spectrum disorder (ASD) affects an estimated 1 in 31 children in the United States by 2025, and prevalence in East Asian countries, such as South Korea, Singapore, and Japan, may be even higher than those in the United States. Despite its increasing prevalence, the underlying causes of ASD remain poorly understood, and there are currently no curative, preventive, or treatment options available. 

A research team from POSTECH and ImmunoBiome in Korea, led by Professor Sin-Hyeog Im, who also serves as the CEO of ImmunoBiome, has made a groundbreaking discovery that reveals a multi-faceted mechanism behind ASD. This study, published in the July issue of Nature Communications (vol. 16, 6422), in collaboration with Dr. John C. Park and Prof. Tae-Kyung Kim, demonstrates that the gut microbiota and host immune system together can influence the progression of ASD in a genetic mouse model.

ASD has long been regarded as a genetically driven disorder. However, growing evidence suggests that environmental and microbial factors also play a role. The human gut harbors more than ten times as many microbial cells as human cells, and these microbes play vital roles in metabolism and the development of the immune system.

In recent years, clinical studies have shown that individuals with ASD have distinct gut microbiota compositions compared to neurotypical controls. Moreover, gastrointestinal comorbidities affect up to 90% of ASD patients, pointing to a potential pathogenic role of gut dysbiosis in ASD. These findings have contributed to the growing gut–brain axis hypothesis, which proposes that gut microbes can influence brain function.

To investigate this further, Prof. Im’s team generated the world’s first germ-free (GF) genetic mouse (BTBR) model for ASD, allowing them to dissect the effects of host genetics, gut microbiota composition, metabolites, and host immune response on ASD progression. Remarkably, GF-ASD mice lacking gut microbiota showed reduced ASD-associated behaviors, suggesting that the gut microbiota, rather than host genetics, may be the dominant driver of ASD symptoms. 

Additionally, GF-ASD mice exhibited reduced neuroinflammation, particularly in inflammatory microglia and a newly identified brain-resident T cell population. By depleting T cells, the researchers were able to prevent ASD-like phenotypes, highlighting a gut-immune-brain signaling pathway in ASD pathology. 

Using 16S-rRNA sequencing and a large-scale metabolomics approach, the researchers found that the gut microbiota influences the balance between glutamate and GABA, two key neurotransmitters that are excitatory and inhibitory, respectively.  An altered glutamate/GABA ratio may directly affect neuronal activity and behavior in ASD. 

To address this imbalance, ImmunoBiome’s AI team developed an in silico model to predict probiotic strains with specific metabolic functions. One such strain, Limosilactobacillus reuteri IMB015, was identified for its ability to uptake glutamate and produce GABA. In ASD mouse models, treatment with IMB015 restored metabolic balance, reduced neuroinflammation, and ameliorated behavioral abnormalities.

ImmunoBiome plans to advance L. reuteri IMB015 as a live biotherapeutic product (LBP) or probiotics for ASD treatment. This includes conducting comprehensive preclinical toxicity evaluations and progressing to clinical trials to assess its safety and therapeutic efficacy in humans.

ImmunoBiome is a leading biotechnology company based in Korea, specializing in the development of Live Biotherapeutic Products (LBPs) for intractable diseases, including cancer, autoimmune disorders, and neurodevelopmental conditions. Through its proprietary Avatiome™ platform, ImmunoBiome develops and rationally selects pharmacologically active bacterial strains, characterizes their immunological mechanisms, and builds therapeutic pipelines based on microbial-derived molecules.

The company maintains a comprehensive database of human commensal bacteria isolated from mucosal surfaces and collaborates closely with POSTECH and global research partners. By integrating AI-based analytics, immune profiling, and microbiome science, ImmunoBiome is pioneering precision microbiome-based therapies and consumer products that aim to modulate host health through the gut–immune–brain axis.

Reference: Park JC, Sim MA, Lee C, et al. Gut microbiota and brain-resident CD4+ T cells shape behavioral outcomes in autism spectrum disorder. Nat Commun. 2025;16(1):6422. doi: 10.1038/s41467-025-61544-0

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