Antibiotic exposure in infants could impair their responses to five important routine vaccines administered daily around the world, new research has found.

Flinders University Associate Professor Lynn says that results of preclinical modelling, and more research in clinical trials, could change the way children are given antibiotics and have significant implications for vaccination programs.

“The research findings are very important because by one year of age, 50 per cent of infants in Australia will be exposed to antibiotics, and this is the period of life that many of these vaccines are administered,” he says.

“It appears that antibiotics in the first year of life change the way the body builds immunity – and responds to vaccination,” says Associate Professor Lynn, who leads the European Molecular Biology Laboratory (EMBL) Australia biomedical informatics group at the Infection and Immunity theme at the South Australian Health and Medical Research Institute (SAHMRI) in Adelaide.

“We have showed that the bacteria in the gut (the microbiome) are important in shaping the strength of the infant immune system,” Associate Professor Lynn says.

“Our findings could have significant implications for vaccination programs globally.”

Published in Cell Host & Microbe today, a research team led by Associate Professor David Lynn, EMBL Australia Group Leader and Flinders University College of Medicine and Public Health reseacher, found that the use of antibiotics in early life (in preclinical animal models) leads to impaired immune responses to five vaccinations routinely given to infants worldwide, including vaccines against meningitis, pneumonia, tuberculosis and whooping cough.

Vaccinations come second only to clean water as the most effective frontline strategies available for preventing infectious diseases. They work by supporting the immune system in producing antibodies against diseases. Antibody-mediated responses play a critical role in vaccine-enabled immunity.

However, for reasons that are poorly understood, these responses vary significantly between individuals.

However, Associate Professor Lynn says the findings support the need to strengthen and repair the healthy gut bugs by replacing them with transplants, prebiotics and probiotics, in food and suitable medications.

In mice, restoring a healthy gut microbiome after antibiotic exposure rescued the impaired vaccine responses.

The team has started a clinical study at the Women’s and Children’s Hospital in Adelaide to identify whether this phenomenon also happens in human infants, and to explore how the healthy gut microbiome influences the effectiveness of vaccination.

EMBL Australia offers powerful new enabling tools such as bioinformatics and systems biology in Australia life science research projects, infrastructure and training programs.

The secretary of the Australasian Virology Society, Flinders University Associate Professor Peter Speck, congratulated the researchers’ work on “emphasising the critical role of the gut microbiome in developing the immune system”.

“In view of the importance of vaccination in maintaining health in society, this is yet another reason why antibiotics should be administered judiciously,” according to Associate Professor Speck, from the College of Science and Engineering at Flinders.

“Antibiotic stewardship is clearly of great value, especially in the neonatal setting,” he says.