About this trial
The goal of this clinical trial is to examine immune responses to the BCG vaccine in healthy adults who have, or who have not, taken antibiotics to deplete their gut bacteria prior to vaccination.
The main question it aims to answer is: does depletion of the gut microbiota lead to impaired BCG-induced protection against specific and non-specific to challenges to the immune system?
Eligibility criteria
This trial accepts healthy volunteersQualifiers
18-35 years old
Provided a signed and dated informed consent form
BCG naïve (Arm 1) and BCG and YF vaccine naïve (Arm 2)
Willing to take short antibiotic course
Disqualifiers
Previous BCG or YF vaccination
Previous YF infection
Evidence of latent TB infection (LTBI) (assessed through a questionnaire) (IGRA to confirm if needed)
malignancies involving bone marrow or lymphoid systems, primary or secondary immunodeficiencies, HIV infection
Trial design
Parallel
Treatments tested in this trial
BCG vaccine
Biological/Vaccine0.1ml injected intradermally over the distal insertion of the deltoid muscle onto the humerus
Yellow Fever vaccine
Biological/Vaccine0.5ml injected subcutaneously
Vancomycin Oral Capsule
Drug500mg every 6 hours for 3 days
Neomycin Oral Product
Drug1000mg every 6 hours for 3 days
Metoclopramide (Maxolon)
Drug10mg every 8 hours
Loperamide HCl
Drug2mg tablets/capsules: 2 tablets/capsules initially, followed by 1 tablet after each loose motion, to a maximum of 8 tablets/capsules per day
Treatment groups
8
Treatment groupsSee each treatment group below.
Trial outcomes
Primary outcomes
Sub-study 1 BCG re-challenge
Mycobacterial load (Colony Forming Units (CFU)) in the skin biopsy site in BCG-vaccinated participants not exposed to antibiotics (BCG-No ABX) compared to BCG-vaccinated participants that were exposed to antibiotics (BCG-ABX)
Sub-study 2 Yellow Fever vaccine
Yellow Fever viremia (viral copies/ml blood) at D3-7 post YF vaccination in BCG-vaccinated participants not exposed to antibiotics (BCG-No ABX) compared to BCG-vaccinated participants that were exposed to antibiotics (BCG-ABX)
Secondary outcomes
Sub-study 1 - Bacterial load
Day 0 bacterial load (16S copies/g stool) in all ABX participants vs No-ABX participants
Sub-study 2 - Bacterial load
Day 0 bacterial load (16S copies/g stool) in all ABX participants vs No-ABX participants
Sub-study 1 - Microbiota diversity
Day 0 microbiota diversity (Shannon diversity index) in all ABX participants vs No-ABX participants
Sub-study 2 - Microbiota diversity
Day 0 microbiota diversity (Shannon diversity index) in all ABX participants vs No-ABX participants
Sponsors and contacts
Click on the lead sponsor to view all of their trials.
South Australian Health and Medical Research Institute
Lead sponsor
Royal Adelaide Hospital
Collaborator
Flinders University
Collaborator
University of Sydney
Collaborator
Telethon Kids Institute
Collaborator
Centenary Institute
Collaborator