Does the gut microbiota impact vaccine responses in infants?

For reasons that are poorly understood, immune responses to vaccination are highly variable among different infants and different populations.

This research group has recently shown that in mice, disruption of the gut microbiota in early life by antibiotic exposure leads to poorer immune responses to multiple different vaccines that are given to infants worldwide.

The Antibiotics and Immune Responses (AIR) study is now investigating whether this is also the case in cohort of nearly 200 infants.

Antibiotics are frequently prescribed to both mother and baby during the pre- and postnatal periods but their impact on the microbiota following birth is poorly understood.

This project will recruit three cohorts of infants from the Women and Children’s Hospital. Cohort 1 will be infants directly exposed to antibiotics, cohort 2 will be infants born to mothers having received intrapartum antibiotics and cohort 3 will be controls which have not been exposed to any antibiotics either directly or in-utero.

All infants will be vaginally-born, healthy and full term. Infants born from mothers with a maternal BMI of more than 30 in the first trimester are excluded. Additionally, infants will be excluded if they or their mothers have sepsis, allergy to a vaccine component, major congenital abnormality, gastrointestinal or other serious disease.

Data on possible confounders are also collected. The team will use high-resolution shotgun metagenomics together with RNA-Seq and flow cytometry to profile how vaccine antibody responses are shaped in early life. Stool samples will be collected for microbiota profiling at weeks 1 and 6 of life. Blood samples will be collected for RNA-Seq and flow cytometry at weeks 6 (pre-vaccination) and 7 (post-vaccination). Antibody responses to infant vaccines (e.g. PCV13, Tetanus, Diphtheria, Pertussis) and will be assessed at 7 and 15 months.

This project is funded by the National Health and Medical Research Council