Immune ResponsesNCT06079606
The Effects of Antibiotic Exposure in Early Infancy on Vaccine Responses
An observational study of Immune Responses and Antibiotic Treatment, run by Landspitali University Hospital at 1 site in Iceland.
Trial summary
This prospective cohort study will include 200 term children born in Landspitali University Hospital in Iceland. The cohort will be divided into four groups according to antibiotic exposure of which one is the control group. Read more about this study
- Who is it for?
- Ages Up to 6 weeksHealthy volunteers can take part
- Conditions the study is for
- Immune Responses, Antibiotic Treatment
- What is being tested?
- Antibiotic treatment
- How many people
- 200 participants
- Where
- 1 siteIceland
- Study dates
- 10 Sep 2022to 31 Dec 2027
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Up to 6 weeks
- All sexes
- Healthy volunteers accepted
- Child
Study population: * Group A: In total 50 term children born in Iceland during the time period 2022-2023, delivered with elective caesarean section (their mothers received intra-operative antibiotics). * Group B: In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and their mothers received intra-partum antibiotics. * Group C: In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and received systemic antibiotics during the first week of life for at least 48 hours. * Control group (Group D): In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and received no systemic antibiotics at the time of recruitment.
Who may be able to join
- All term children born in Iceland from 2022-2023
Who cannot join
- Children born with emergency caesarean section
- Children born before 36 weeks of gestation
- Children diagnosed with primary or secondary immunodeficiency
- Use of immunosuppressive drugs at recruitment or during the follow up period (excluding inhaled corticosteroids and short term oral corticosteroids (<3 consecutive days).
- Children with chromosomal, genetic or other congenital diseases or abnormalities
- Children with severe, chronic diseases or disabilities
- Informed consent not signed by parents
Trial locations and contacts
1 site in 1 country.
About this study
This prospective cohort study will include 200 term children born in Landspitali University Hospital in Iceland. The cohort will be divided into four groups according to antibiotic exposure of which one is the control group. Children's immune responses to live oral rotavirus vaccine as well as conventional vaccinations given at three, five and 12 months old will be determined by measuring salivary and serologic responses. Responses will be compared between the four groups. Stool samples will also be collected from participants and the composition of the microbiome compared between the four groups.
Read the detailed description
This prospective cohort study will evaluate the development of the immune system by means of evaluating the immune responses to oral rotavirus vaccine and the scheduled childhood vaccinations in Iceland, at the age of three, five and 12 months, in four different groups of term children born in Iceland.
The cohort will be divided into the following groups:
- Group A: Term children born with elective caesarean section (their mothers received intra-operative antibiotics).
- Group B: Term vaginally born children and their mothers received intra-partum antibiotics.
- Group C: Term vaginally born children that received systemic antibiotics during the first week of life for at least 48 hours.
- Group D: Term vaginally born children that had not received systemic antibiotics at the time of recruitment.
Parents of children born with elective caesarean section in Landspitali or born vaginally and their mothers received intra-partum antibiotics as well as parents of children in the Neonatal Intensive Care Unit receiving systemic antibiotics during the first week of life will be offered to take part in the study (Groups A, B and C). Parents of children coming to a five day old check up at the Children's Hospital in Landspitali will also be offered to take part in the study (Group D). Sample size calculations show that to detect a 30% difference in immune responses to vaccines with 80% power, 40 infants are needed for analysis in each group. To account for late exclusions due to antibiotic use or drop-out due to other reasons, 50 infants will be recruited to each group. Participants will receive vaccination with the oral live attenuated rotavirus vaccine, Rotarix, at six weeks old and again at three months old. Participants will receive vaccinations with Pentavac against diphtheria, tetanus, pertussis, haemophilus influenza type B and polio and Synflorix against pneumococci at their Health Care Centre according to scheduled childhood vaccinations in Iceland at three, five and 12 months old. Salivary and blood samples will be taken from participants just before the first vaccination with Rotarix at six weeks old and again at six months (four weeks after the second dose of Pentavac and Synflorix) and at 13 months old (four weeks after the third dose of Pentavac and Synflorix). Specific antibody levels against rotavirus, pertussis, diphtheria, tetanus, haemophilus influenzae type B, polio virus and pneumococci will be measured. Parents of participants will be given two stool sample kits and asked to take one from their child at six weeks old (before the first dose of rotavirus vaccine) and then another at three months old. In case of detection of differences in antibody response, these samples will be sent for microbiome analysis.
- Conditions
- Immune Responses, Antibiotic Treatment
- Being tested
- Antibiotic treatment
- Keywords
- Antibiotics, Immune Responses, Vaccinations, Children, Rotavirus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Antibiotic treatmentOther
Children will be assigned to groups according to antibiotic exposure in early life. No antibiotics will be given in the study.
| Study group | Role | What they receive |
|---|---|---|
| Group A | Term children born with caesarean section (their mothers received intra-operative antibiotics) Receives: Other: Antibiotic treatment | |
| Group B | Term vaginally born children and their mothers received intra-partum antibiotics Receives: Other: Antibiotic treatment | |
| Group C | Term vaginally born children that received systemic antibiotics during the first week of life for at least 48 hours Receives: Other: Antibiotic treatment | |
| Group D (Control group) | Term vaginally born children that had not received systemic antibiotics at the time of recruitment |
What is being measured
The primary outcome is the main question the study is designed to answer.
Serum antibody response to rotavirus
Serum IgA against rotavirus
Measured: 2 years
Salivary antibody response to rotavirus
Salivary IgA levels against rotavirus
Measured: 2 years
Serum antibody response to other microbes
Serum IgG against other microbes
Measured: 2 years
Salivary antibody response to other microbes
Salivary IgG against other microbes
Measured: 2 years
Secondary outcomes (1)
Composition of the microbiome
16s rRNA analysis of stool microbiome
Measured: 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Oct 2023
- Study start10 Sep 2022
- Primary completion28 Feb 2025
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Immune ResponsesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Landspitali University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06079606
- Sponsor's protocol ID
- e-INFANT-2
- Status last verified
- Sep 2025
- First submitted
- 6 Oct 2023
- Last updated
- 18 Dec 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 18 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Antibiotic Exposure in Early Infancy on Vaccine Responses
- ClinicalTrials.gov ID
- NCT06079606
- Acronym / sponsor ID
- e-INFANT-2
- Conditions
- Immune Responses, Antibiotic Treatment
- Keywords
- Antibiotics, Immune Responses, Vaccinations, Children, Rotavirus
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Landspitali University HospitalUniversity, hospital or other
- Study start
- 10 Sep 2022 (actual)
- Primary completion
- 28 Feb 2025 (actual)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 12 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective cohort study will include 200 term children born in Landspitali University Hospital in Iceland. The cohort will be divided into four groups according to antibiotic exposure of which one is the control group. Children's immune responses to live oral rotavirus vaccine as well as conventional vaccinations given at three, five and 12 months old will be determined by measuring salivary and serologic responses. Responses will be compared between the four groups. Stool samples will also be collected from participants and the composition of the microbiome compared between the four groups.
Detailed description
This prospective cohort study will evaluate the development of the immune system by means of evaluating the immune responses to oral rotavirus vaccine and the scheduled childhood vaccinations in Iceland, at the age of three, five and 12 months, in four different groups of term children born in Iceland.
The cohort will be divided into the following groups:
- Group A: Term children born with elective caesarean section (their mothers received intra-operative antibiotics).
- Group B: Term vaginally born children and their mothers received intra-partum antibiotics.
- Group C: Term vaginally born children that received systemic antibiotics during the first week of life for at least 48 hours.
- Group D: Term vaginally born children that had not received systemic antibiotics at the time of recruitment.
Parents of children born with elective caesarean section in Landspitali or born vaginally and their mothers received intra-partum antibiotics as well as parents of children in the Neonatal Intensive Care Unit receiving systemic antibiotics during the first week of life will be offered to take part in the study (Groups A, B and C). Parents of children coming to a five day old check up at the Children's Hospital in Landspitali will also be offered to take part in the study (Group D). Sample size calculations show that to detect a 30% difference in immune responses to vaccines with 80% power, 40 infants are needed for analysis in each group. To account for late exclusions due to antibiotic use or drop-out due to other reasons, 50 infants will be recruited to each group. Participants will receive vaccination with the oral live attenuated rotavirus vaccine, Rotarix, at six weeks old and again at three months old. Participants will receive vaccinations with Pentavac against diphtheria, tetanus, pertussis, haemophilus influenza type B and polio and Synflorix against pneumococci at their Health Care Centre according to scheduled childhood vaccinations in Iceland at three, five and 12 months old. Salivary and blood samples will be taken from participants just before the first vaccination with Rotarix at six weeks old and again at six months (four weeks after the second dose of Pentavac and Synflorix) and at 13 months old (four weeks after the third dose of Pentavac and Synflorix). Specific antibody levels against rotavirus, pertussis, diphtheria, tetanus, haemophilus influenzae type B, polio virus and pneumococci will be measured. Parents of participants will be given two stool sample kits and asked to take one from their child at six weeks old (before the first dose of rotavirus vaccine) and then another at three months old. In case of detection of differences in antibody response, these samples will be sent for microbiome analysis.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Group A | – | Other: Antibiotic treatmentTerm children born with caesarean section (their mothers received intra-operative antibiotics) |
| Group B | – | Other: Antibiotic treatmentTerm vaginally born children and their mothers received intra-partum antibiotics |
| Group C | – | Other: Antibiotic treatmentTerm vaginally born children that received systemic antibiotics during the first week of life for at least 48 hours |
| Group D (Control group) | – | –Term vaginally born children that had not received systemic antibiotics at the time of recruitment |
Who may qualify
- Ages
- Up to 6 weeks
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
- Study population
- * Group A: In total 50 term children born in Iceland during the time period 2022-2023, delivered with elective caesarean section (their mothers received intra-operative antibiotics). * Group B: In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and their mothers received intra-partum antibiotics. * Group C: In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and received systemic antibiotics during the first week of life for at least 48 hours. * Control group (Group D): In total 50 term children born in Iceland during the time period 2022-2023, delivered vaginally and received no systemic antibiotics at the time of recruitment.
Key inclusion criteria (1 listed)
- All term children born in Iceland from 2022-2023
Key exclusion criteria (7 listed)
- Children born with emergency caesarean section
- Children born before 36 weeks of gestation
- Children diagnosed with primary or secondary immunodeficiency
- Use of immunosuppressive drugs at recruitment or during the follow up period (excluding inhaled corticosteroids and short term oral corticosteroids (<3 consecutive days).
- Children with chromosomal, genetic or other congenital diseases or abnormalities
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Antibiotic treatmentChildren will be assigned to groups according to antibiotic exposure in early life. No antibiotics will be given in the study. | Other | Group A, Group B, Group C |
Primary outcome
Serum antibody response to rotavirus
Time frame: 2 years
Serum IgA against rotavirus
Salivary antibody response to rotavirus
Time frame: 2 years
Salivary IgA levels against rotavirus
Serum antibody response to other microbes
Time frame: 2 years
Serum IgG against other microbes
Salivary antibody response to other microbes
Time frame: 2 years
Salivary IgG against other microbes
1 secondary outcome
Composition of the microbiome
Time frame: 3 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Dec 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Immune Responses and Antibiotic Treatment, run by Landspitali University Hospital at 1 site in Iceland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 18 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Iceland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Serum antibody response to rotavirus (time frame: 2 years). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Dec 2025.