Infant RSV Immunity Study (IRIS)

June 11, 2026 updated by: Pascal Lavoie, University of British Columbia

Understanding the Impact of Early-life RSV Infections on Infant Immunity and Long-term Health

Respiratory Syncytial Virus (RSV) is a main global cause of respiratory illness and death in infants. Previous infant vaccine trials have failed to demonstrate protection. Moreover, RSV infection during early infancy, particularly in infants younger than 4 months of age, is associated with more severe disease, reduced immune protection, and an increased risk of developing childhood asthma. This study aim to investigate the immunological and long-term health effects of a first exposure to RSV early (<4 months) versus late (>6-9 months) in infancy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

In British Columbia (Canada), RSV cases rise each year after mid-October, until April, peaking in December. This study compares outcomes between infants born in April to June, who will be naturally exposed to RSV >6-9 months of age versus infants born in September to November, who will be naturally exposed to RSV <4 months of age. Most infants become infected during their first RSV year.

Primary Objectives:

  1. Compare post-season RSV immune responses between the spring cohort of infants born in April to June versus the fall cohort of infants born in September to November.
  2. Compare respiratory outcomes at 3 years of age between the spring cohort of infants born in April to June versus the fall cohort of infants born in September to November.

Secondary Objectives:

  1. Identify immune maturation events linked to stronger post-season RSV antibody responses.
  2. Determine how the gut and upper airway microbiota co-evolve in infants over the first year of life, and how these dynamics shape RSV risk, and are shaped by host-related, and specifically seasonal factors (i.e. Apr-Jun versus Sept-Nov).
  3. Compare immune responses during acute RSV infections between the spring cohort of infants born in April to June versus the fall cohort of infants born in September to November.

Design:

Prospective, observational cohort study of 300 parent-infant pairs born in the spring (April-June) or fall (Sept-Nov), with follow-up at 3 years of age.

Recruitment and Informed Consent Procedure:

Birthing parents planning to give birth at the BC Women's Hospital or live locally in greater Vancouver are identified through the BC Women's Hospital prenatal ultrasound clinic or social media and contacted by the study coordinator in person, by telephone or by text message. Interested participants complete an online eligibility questionnaire and, if eligible, the online consent form. Study advertisements posted in the hospital, local clinics, local community centers and on social media direct interested parents to the study website, online eligibility questionnaire and the study coordinators contact information.

Patients who delivered an infant during the study eligibility period in the Vancouver Coastal Health region are also invited by mail and enrolled prior to the start of the respiratory season for the spring cohort (September/October 2026) or prior to the post-season study visit for the fall cohort (May/June 2027).

Written informed consent is obtained from all participants prior to study procedures. The study has been approved by the University of British Columbia Children's and Women's Research Ethics Board (H25-02623).

Study Procedures:

At enrollment, parents are asked to complete a baseline questionnaire that collects basic pregnancy information (e.g. maternal age, pregnancy conditions, number of babies in pregnancy), intention to receive or receipt of RSV maternal vaccine, household size / number of siblings at home and their ages, smoking, family history of asthma/use of inhalers, use of antibiotics during pregnancy, family history of atopy / asthma, presence of furry pets in the home.

In each post-season questionnaire, parents are also additionally asked about socioeconomic factors, travel, daycare use, child medication use, child hospitalization or medical visit for a respiratory infection and if their child experienced asthma or wheezing symptoms. Study staff review hospital charts at birth and each year after the respiratory season to gather information about RSV-related hospitalizations and RSV testing.

Parents complete a child feeding questionnaire at 3, 6 and 12 months to collect information on infant/child dietary intake including breastfeeding and formula use (start/end dates, duration) and introduction of solid foods.

Biospecimen Collection:

A cord blood sample collected at delivery. If cord blood cannot be collected, a peripheral blood sample is taken at a scheduled study visit within one month after birth, at BC Children's Hospital. If enrolled greater than 1 month after delivery, cord/peripheral blood is not collected. To account for pre-season RSV antibody levels in the analysis, an additional pre-season dried blood spot (DBS) sample are collected in September from the spring cohort babies. We also obtain a residual sample from the Newborn Screening DBS at birth in all infants, for measurements of RSV antibody levels and neutralization titers.

A post-season blood sample is collected from all participants at a scheduled study visit at BC Children's Hospital in May or June following the RSV season.

Serology samples are used to quantify RSV antibodies and neutralization titers, and RSV F-specific antibody-dependent function.

Cord blood and peripheral blood mononuclear cells are stored from the cord and post-natal blood samples, to measure RSV T and B cell responses. A sample is also stored for whole blood RNA-Sequencing studies (PAXgene).

Prenatal and delivery serology samples are obtained from routine samples collected from birthing parents. An additional maternal blood sample is collected at the scheduled post-season study visit in May or June 2027.

RSV Testing and Respiratory Outcome Questionnaires:

Infants are monitored for respiratory outcomes (wheezing episodes) throughout each RSV season (September to March) using parent-completed diaries and parent-collected nasal swab testing when child exhibit pre-defined symptom criteria for infection (e.g. fever, cough, nasal congestion, difficulty breathing).

A subset of infants who test positive for RSV during the acute illness are invited to provide a blood sample about 2 weeks into the acute illness.

Diaries will be used for parents to record each episode of a respiratory infection, the severity and duration of the episode, and to track wheezing days.

Microbiome Studies:

A subset of at least 50 birthing parents in each (Apri-Jun / Sept/Nov) group provide a self-collected vaginal swab within 2 weeks after birth.

Oral swabs are collected from the infants around 2 weeks of age. In addition, stool samples are collected on children at 3, 6, 9 and 12 months of age. For children recruited greater than 1 month after delivery, microbiome samples are not collected.

Main Outcomes:

The study sample size is determined based on the respiratory outcome at 3 years, using the Child Healthy Infant Longitudinal Development study has developed and validated the (CHILDhood Asthma Risk Tool) CHART tool.

The main post-season outcomes are RSV antibody levels and neutralization, with main comparisons between the spring and fall groups/cohorts.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
300

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Pascal Lavoie, MDCM PhD FRCPC
  • Phone Number: 604-875-2135
  • Email: plavoie@bcchr.ca

Study Contact Backup

  • Name: Allison Watts, PhD
  • Phone Number: 6705 604-875-2000
  • Email: awatts@bcchr.ca

Study Locations

  • Canada
    • British Columbia
      • Vancouver, British Columbia, Canada, V6H 3N1
        • Recruiting
        • BC Women's Hospital and Health Centre
        • Contact:
          • Pascal Lavoie, MD PhD
          • Phone Number: 7318 (604) 875-2000
          • Email: plavoie@bcchr.ca
        • Contact:
        • Principal Investigator:
          • Pascal Lavoie, MD PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Birthing parents who have a due date or delivery date in April, May or June 2026 (spring group/cohort) or September, October or November 2026 (fall group/cohort) with follow-up of the birthing parent and child during the 2026-2027, 2027-2028 and 2028-2029 RSV seasons. Children will be followed up to 3 years of age. The cohort will consist of 300 birthing parent-child pairs, with 150 in the spring cohort and 150 in the fall cohort. Birthing parents are recruited during antenatal care or shortly after delivery from the ultrasound clinic or delivery wards at BC Women's Hospital, patient lists from local maternity wards within the Vancouver Coastal Health Authority or advertisements at local prenatal care centres (obstetrician, physician and midwife clinics), community centres or on social media.

Description

Inclusion Criteria:

Birthing parent/child pairs with a delivery date in April, May or June or September, October or November who delivered or are planning to deliver at BC Women's Hospital + Health Centre or a nearby, local hospital.

Exclusion Criteria:

Severe pregnancy-related complications or chronic medical conditions in the children making them automatically eligible to receiving RSV immunoprophylaxis in British Columbia (e.g. infants born prematurely < 35 weeks of gestation, or with chronic medical conditions).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Fall group/cohort
Infants exposed to RSV <4 months of age (born September-November)
Spring group/cohort
Infants exposed to RSV >6-9 months of age (born April-June)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
RSV antibody response
Time Frame: Post-respiratory season 2027 (May 2027)
i) RSV neutralization titers (expressed as dilution titer to prevent 95% neutralization in vitro; NT95) ii) RSV F-specific antibody-mediated complement activation iii) RSV F-specific antibody-mediated phagocytosis
Post-respiratory season 2027 (May 2027)
Asthma symptoms
Time Frame: at age 3 years old
Children will be categorized as having low, moderate or high risk of asthma based on asthma-like symptoms defined using the Childhood Asthma Risk Tool (CHART)
at age 3 years old

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Medically attended RSV infections
Time Frame: At 1 year and 3 years of age
Incidence of RSV and Lower Respiratory Tract Infection hospitalizations and medically attended RSV infections
At 1 year and 3 years of age
Wheezing
Time Frame: During first RSV season (Sept to April), and each season, up to 3 years of age (for number of wheezing days during season).
Proportion of infants who develop persistent wheezing after their first RSV episode, and the number of wheezing days during season, and after each episode of RSV infection.
During first RSV season (Sept to April), and each season, up to 3 years of age (for number of wheezing days during season).

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Gut and upper airway microbiota
Time Frame: 0, 3, 6, 9 and 12 months
Characterization of gut and upper airway microbiota, with quantification of within- (α-diversity; Shannon index) and between-sample (β-diversity; Bray-Curtis or UniFrac) diversity.
0, 3, 6, 9 and 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of British Columbia

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
June 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 11, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 11, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 17, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 17, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 11, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • F25-01060

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Pending approval by our local Research Ethics Board.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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