Effectiveness of ABRYSVO® Maternal Respiratory Syncytial Virus (RSV) Vaccine Against RSV in Infants in Western Pennsylvania

NCT ID: NCT06813872

Last Updated: 2025-11-19

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Total Enrollment: 1 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-02-24
• Study Completion Date: 2027-07-31

Brief Summary

Globally, respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease (LRTD) in infants. Pfizer has developed ABRYSVO-a bivalent RSV prefusion F protein-based vaccine (RSVpreF) composed of two prefusion F proteins to protect against both RSV-A and RSV-B. In the United States, ABRYSVO has been approved and recommended for active immunization of pregnant individuals from 32 0/7 to 36 6/7 weeks' gestational age for the prevention of LRTD and severe LRTD caused by RSV in infants from birth through 6 months of age. To generate critical evidence to support vaccine policy and implementation, Pfizer will collaborate with University of Pittsburgh to study vaccine effectiveness (VE) of ABRYSVO vaccination during pregnancy against RSV-associated outcomes in infants. The study will take place in a real-world population in Western Pennsylvania over multiple seasons, beginning in the 2023-2024 season, and will use a test negative design (TND approach). There will be no active enrollment of study participants, no direct contact with study participants, and no collection of any primary data outside of the Standard of Care (SOC). This study will use a TND to evaluate real-world VE of maternal ABRYSVO against RSV-associated outcomes in infants. Additionally, we will describe RSV-associated medically-attended visits for infants exposed to ABRYSVO and Beyfortus (monoclonal antibody (MAB) administered to babies up to 24 months for protection against RSV).

Conditions

Respiratory Syncytial Viruses

Study Design

• Observational Model Type: CASE_CONTROL
• Study Time Perspective: RETROSPECTIVE

Study Groups

Case

Cases for the primary objective will be infants meeting the outcome definition who had any positive laboratory-confirmed RSV test from a respiratory sample collected within 10 days prior to hospital admission through 3 days after hospital admission.

ABRYSVO Vaccination

Intervention Type: BIOLOGICAL

The primary exposure of interest for the TND study is maternal history of vaccination with Pfizer's ABRYSVO vaccine during pregnancy with the infant who presented for care. Infants will be considered "exposed to ABRYSVO" if their birth parent has documented evidence of receiving ABRYSVO ≥14 days before the date of the infant's birth, during the licensed gestational age window of 32 0/7 to 36 6/7 weeks.

Control

Controls for the primary objective will be infants meeting the outcome definition who had a laboratory-confirmed negative RSV test from a respiratory sample collected within 10 days prior to hospital admission through 3 days after hospital admission.

ABRYSVO Vaccination

Intervention Type: BIOLOGICAL

The primary exposure of interest for the TND study is maternal history of vaccination with Pfizer's ABRYSVO vaccine during pregnancy with the infant who presented for care. Infants will be considered "exposed to ABRYSVO" if their birth parent has documented evidence of receiving ABRYSVO ≥14 days before the date of the infant's birth, during the licensed gestational age window of 32 0/7 to 36 6/7 weeks.

Interventions

ABRYSVO Vaccination

The primary exposure of interest for the TND study is maternal history of vaccination with Pfizer's ABRYSVO vaccine during pregnancy with the infant who presented for care. Infants will be considered "exposed to ABRYSVO" if their birth parent has documented evidence of receiving ABRYSVO ≥14 days before the date of the infant's birth, during the licensed gestational age window of 32 0/7 to 36 6/7 weeks.

Intervention Type: BIOLOGICAL

Eligibility Criteria

Exclusion Criteria

1. Infants who received any licensed or investigational RSV preventive product (e.g., palivizumab, Beyfortus, active RSV vaccine (including investigational products or due to medication error) since birth.

2. Born to birth parent for whom ABRYSVO vaccination status cannot be verified in the maternal electronic health record or Pennsylvania Immunization Electronic Registry System (PIERS) system.

3. Infants who were born to an individual vaccinated with any other licensed or investigational RSV vaccine during pregnancy.

• Minimum Eligible Age: 0 Months
• Maximum Eligible Age: 6 Months
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Pfizer

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Pfizer CT.gov Call Center

Role: STUDY_DIRECTOR

Pfizer

Locations

Pfizer

New York, New York, United States

Countries

United States

Related Links

https://pmiform.com/clinical-trial-info-request?StudyID=C3671074

To obtain contact information for a study center near you, click here.

Other Identifiers

CASSATT

Identifier Type: OTHER

Identifier Source: secondary_id

C3671074

Identifier Type: -

Identifier Source: org_study_id