Effectiveness of ABRYSVO® maternal respiratory syncytial virus (RSV) vaccine against RSV in infants in Western Pennsylvania (CASSATT)

Study identification

• EU PAS number:
  EUPAS1000000389
• Study ID:
  1000000389
• Official title and acronym:
  Effectiveness of ABRYSVO® maternal respiratory syncytial virus (RSV) vaccine against RSV in infants in Western Pennsylvania (CASSATT)
• DARWIN EU® study:
  No
• Study countries:
  United States
• Study description:
  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).
• Study status:
  Planned

Research institutions and networks

Institutions

University of Pittsburgh

Study timelines

Date when funding contract was signed

Actual:16/10/2024

Study start date

Planned:24/02/2025

Date of final study report

Planned:20/12/2027

Sources of funding

Pharmaceutical company and other private sector 

More details on funding

Pfizer, Inc

Regulatory

• Was the study required by a regulatory body?:
  No
• Is the study required by a Risk Management Plan (RMP)?:
  Not applicable