A Randomised Controlled Trial to Assess if a Probiotic Intervention Leads to Enhanced Immune Responses to Vaccination in Antibiotic-treated Infants (Bloom Infant Probiotic (BIP) Study)

What this Trial Is About

This research aims to evaluate if giving a probiotic called Infloran4 to infants who received antibiotics in their first 28 days can improve their immune response to routine vaccines. Early antibiotic use may reduce beneficial gut bacteria important for immunity, potentially leading to weaker vaccine responses. The study will compare immune responses between infants receiving Infloran4 and those receiving a placebo. Participants will be randomly assigned to receive either a 14-day course of the probiotic Infloran4, containing Bifidobacterium bifidum and Lactobacillus acidophilus, or a placebo that looks identical but contains no bacteria. The probiotic or placebo will be given orally by dissolving the capsule contents in a small amount of breast milk, formula, or sterile water. Routine vaccinations will be given at 6 weeks, 4 months, and 6 months following the National Immunisation Program. During the study, infants will provide blood samples at 6 weeks, 6.5 weeks (optional), 6 months, and 12 months to measure antibody levels and immune responses. Stool samples will be collected before treatment, on day 7, day 14 after treatment, and before the first vaccination. Surveys will gather information on treatment administration and vaccination side effects. The main outcome is the level of antibodies against pneumococcal vaccine serotypes at 6 months. The study will last until infants reach 12 months of age to see if the probiotic improves vaccine immunity.

The Bloom Infant Probiotic (BIP) Study