The Bloom Infant Probiotic (BIP) Study

Summary

The goal of this clinical trial is to investigate whether administering a probiotic (Infloran®) to infants who received antibiotics in the first 28 days of life can restore or enhance their immune response to routine vaccines.

Antibiotic use in the first weeks of life can lower the levels of beneficial gut bacteria, such as bifidobacteria, which play a key role in immune function. As a result, infants treated with antibiotics may produce fewer antibodies after routine vaccinations, leaving them less protected against infections.

The main questions this study aims to answer are:

* Does treatment with the probiotic Infloran® improve the geometric mean concentrations (GMCs) of anticapsular antibodies against at least 11 serotypes included in the pneumococcal conjugate vaccine (PCV20) in serum samples collected at 6 months of age compared with placebo in infants treated with antibiotics in the neonatal period?
* Does treatment with the probiotic Infloran® improve the GMCs for the pneumococcal conjugate vaccine (PCV20) at 12 months of age compared with placebo in infants treated with antibiotics in the neonatal period?
* Does treatment with the probiotic Infloran® improve the GMCs of other routine childhood vaccines at 6 and 12 months of age compared with placebo in infants treated with antibiotics in the neonatal period?
* Does treatment with the probiotic Infloran® increase the proportion of infants achieving seroprotective antibody levels for pneumococcal antigens compared to placebo in infants treated with antibiotics in the neonatal period?
* What are the differences in antigen specific T cell responses, flow cytometry, blood transcriptomics, and gut microbiota composition in the probiotic (Infloran®) vs placebo groups in infants treated with antibiotics in the neonatal period?

Researchers will compare infants who receive Infloran® (a probiotic containing Bifidobacterium bifidum and Lactobacillus acidphilus) with those who receive a placebo (which contains the same excipients as Infloran® but does not contain any bacterial strains).

Participants will:

* Be randomly assigned to receive either a 14-day course of probiotic Infloran® or a placebo.
* Provide blood samples (3-5 mL) at 6 weeks, 6.5 weeks (optional blood-draw for exploratory endpoint), 6 months and 12 months of age.
* Provide stool samples at four timepoints: prior to starting the intervention (probiotic/placebo), on day 7, on day 14 after completion of the study supplement, and prior to their first vaccination at 6 weeks of age.
* Receive routine vaccinations at 6 weeks, 4 months and 6 months in line with the National Immunisation Program
* Complete surveys to collect information regarding probiotic/placebo administration and vaccination related side effects

This study aims to recruit 360 infants to assess whether this probiotic treatment following antibiotic exposure improves the immunogenicity of vaccinations. The information from this study will improve our understanding of how probiotic intervention can support optimal immune responses to vaccination in early life. The findings could potentially influence public health strategies, offering a new way to support optimal vaccine responses in antibiotic-treated infants.

Conditions

• Infant, Newborn
• Immunity
• Immunisation
• Antibiotic Treatment
• Microbiome Dysbiosis

Interventions

DRUG

Probiotic

Probiotic capsule contents will be dissolved in a small amount of breast milk, formula or sterile water (drinking water boiled, then cooled) and administered by the infant's parent/guardian to infants as an oral bolus dose. Probiotic Infloran® Hard capsules (Bifidobacterium bifidum \& Lactobacillus acidophilus) are a listed medicine on the Australian Register of Therapeutic Goods (ARTG). Infloran® has been previously used in infants including pre-term infants for other indications including supporting healthy digestion or improving digestive system flora. Infloran® is manufactured by Laboratorio Farmaceutico SIT S.r.l., Via Cavour 70 - 27035 Mede (PV) Italy.

DRUG

Matching placebo

Placebo contains the same excipients as Infloran, it is also made from the same capsule, but it does not contain any bacterial strains. Placebo capsule contents will be dissolved in a small amount of breast milk, formula or sterile water (drinking water boiled, then cooled) and administered by the infant's parent/guardian to infants as an oral bolus dose. The placebo is manufactured by Syntro Health, 558-562 Swan St, Richmond, VIC 3121.

Sponsors & Collaborators

• Flinders University

  collaborator OTHER

• Women's and Children's Hospital, Adelaide

  collaborator UNKNOWN

• Flinders Medical Center

  collaborator UNKNOWN

• Women's & Children's Hospital Foundation

  collaborator UNKNOWN

• The University of Western Australia

  collaborator OTHER

• South Australian Health and Medical Research Institute

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Max Age

28 Days

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-05-31

Primary Completion

2029-04-30

Completion

2029-10-31

Countries

• Australia

Study Locations