NCT06813872

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

• Status: Active Not Recruiting
• Phase: —
• Study type: Observational
• Enrollment: 1 (actual)
• Sponsor: Pfizer · Industry
• Sex: All
• Age: 0 Months – 6 Months
• Healthy volunteers: Not accepted

Summary

Globally, respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease (LRTD) in infants and children. 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 320/7 to 366/7 weeks' gestational age for the prevention of LRTD and severe LRTD caused by RSV in infants from birth through 6 months of age. Post-licensure data from the United States and Argentina have also demonstrated real world effectiveness. Data from the US VISION and NVSN networks reported 79% (95% CI 55-90) and 70% (95% CI 28-88%) VE respectively against RSV-associated hospitalization among infants in the second RSV season and a study from Argentina reported 78.6% (95% CI 62.1-87.9) and 71.3% (95% CI 53.3-82.3) VE against RSV-associated LRTD leading to hospitalization among infants aged 0 to ≤3 and 0 to ≤6 months respectively. 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 RSV monoclonal antibodies (e.g., Beyfortus and Enflonsia).

Conditions

• Respiratory Syncytial Viruses

Interventions

Type	Name	Description
BIOLOGICAL	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.

Timeline

• Start date: 2025-02-24
• Primary completion: 2027-07-31
• Completion: 2027-07-31
• First posted: 2025-02-07
• Last updated: 2026-02-03

Locations

1 site across 1 country: United States