Among non-pregnant adults observed in Epic Cosmos since August 2023 who are eligible for RSV vaccination, what is the effectiveness of ABRYSVO® (RSVpreF), compared with unvaccinated individuals, in preventing RSV-related and all-cause acute respiratory illness (ARI), lower respiratory tract disease (LRTD), and other outcomes of interest, within a target trial emulation (TTE) framework

Inclusion: Vaccinated Cohort

Patients must meet all the following inclusion criteria to be eligible for inclusion in the vaccinated cohort:

Adults meet the age criteria at the index date. Non-pregnant at the index date. Have at least one clinical encounter recorded in Epic Cosmos database during the 12 months prior to the index date.

Have a documented administration of ABRYSVO® (or AREXVY®，mRESVIA® in the later phase) in Epic Cosmos on or after August 2023.

The index date for vaccinated individuals will be defined as the date of RSV vaccination.

Unvaccinated Cohort

Patients must meet all the following inclusion criteria to be eligible for inclusion in the unvaccinated cohort:

Adults meet the age criteria at the index date. Non-pregnant at the index date. Have at least one clinical encounter recorded in Epic Cosmos database during the 12 months prior to the index date.

Have no documented receipt of any RSV vaccine in Epic Cosmos on or prior to the trial start date.

The index date for unvaccinated individuals will be defined as the start date of each sequential trial (e.g., 1st date of each month) in which they met eligibility criteria.

Exclusion:

Vaccinated Cohort

Patients meeting any of the following criteria will not be included in the vaccinated cohort:

Individual with receipt of any RSV vaccine in Epic Cosmos prior to the trial start date, as defined above (applicable to all analyses except for the analysis of recipients of multiple doses).

Non-US residents. Unvaccinated Cohort

Patients meeting any of the following criteria will not be included in the unvaccinated cohort:

Individual with receipt of any RSV vaccine in Epic Cosmos on or prior to the trial start date, as defined above.

Non-US residents. Patients must meet all the inclusion criteria and none of the exclusion criteria to meet eligibility requirements.

The study population will include non-pregnant adults aged ≥18 years and ≥ 60 years in the United States with care observed in Epic Cosmos, contributing healthcare systems on or after August 2023. Individuals will be required to have sufficient healthcare engagement to ensure adequate data capture and observability within the database. Within this population, vaccinated individuals will be identified by documented administration of an RSV vaccine in structured EHR data.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.