Respiratory Syncytial Virus (RSV)NCT07673081
Real-World Effectiveness of RSV Vaccines Among Adults Using Target Trial Emulation in Epic Cosmos
An observational study of Respiratory Syncytial Virus (RSV), run by Pfizer at 1 site in United States.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Respiratory Syncytial Virus (RSV)
- Type of treatment
- Vaccines
- How many people
- 293,334 participants
- Where
- 1 siteUnited States
- Study dates
- 22 Jun 2026to 30 Sep 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: 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.
Who may be able to join
- 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:
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- 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.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
About this study
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
- Conditions
- Respiratory Syncytial Virus (RSV)
- Keywords
- RSV, Respiratory Syncytial Virus, Vaccine effectivness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Vaccinated group | Individuals with documented receipt of an RSV vaccine in EHR data. Vaccines included: ABRYSVO® (Pfizer),AREXVY® (GSK), mRESVIA® (Moderna) | |
| Unvaccinated comparator group: | Individuals not yet vaccinated at cohort entry, but otherwise eligible |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of RSV-related Acute Respiratory Infection (ARI) hospitalization
Measured: up to 3 years
Incidence of RSV-related Lower Respiratory Tract Disease (LRTD) hospitalization
Measured: up to 3 years
Secondary outcomes (2)
Incidence of RSV-related outcomes
ARI/LRTD non-inpatient encounter, ARI/LRTD severe outcome, ARI/LRTD critical outcome, CV events with different care settings, thromboembolic event with different care settings, asthma exacerbation with different care settings, COPD exacerbation with different care settings, and pneumonia with different care settings.
Measured: up to 3 years
Incidence of All-cause outcomes
all-cause ARI/LRTD encounter with different care settings, severe outcome, critical outcome, CV events with different care settings, thromboembolic event with different care settings, asthma exacerbation with different care settings, COPD exacerbation with different care settings, pneumonia with different care settings, and dementia (new onset).
Measured: up to 3 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jun 2026
- Study start22 Jun 2026
- Primary completion30 Sep 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Respiratory Syncytial Virus (RSV)Studies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 293,334 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Ividence
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07673081
- Sponsor's protocol ID
- C3671094
- Status last verified
- Aug 2026
- First submitted
- 22 Jun 2026
- Last updated
- 20 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: 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.
Study at a glance
From the registry record, last updated by the sponsor on 20 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Real-World Effectiveness of RSV Vaccines Among Adults Using Target Trial Emulation in Epic Cosmos
- ClinicalTrials.gov ID
- NCT07673081
- Acronym / sponsor ID
- C3671094
- Conditions
- Respiratory Syncytial Virus (RSV)
- Keywords
- RSV, Respiratory Syncytial Virus, Vaccine effectivness
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 293,334 participants (estimated)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Collaborators
- Ividence
- Study start
- 22 Jun 2026 (actual)
- Primary completion
- 30 Sep 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 29 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Vaccinated group | – | –Individuals with documented receipt of an RSV vaccine in EHR data. Vaccines included: ABRYSVO® (Pfizer),AREXVY® (GSK), mRESVIA® (Moderna) |
| Unvaccinated comparator group: | – | –Individuals not yet vaccinated at cohort entry, but otherwise eligible |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- 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.
Key inclusion criteria (9 listed)
- 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
Key exclusion criteria (7 listed)
- 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:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Incidence of RSV-related Acute Respiratory Infection (ARI) hospitalization
Time frame: up to 3 years
Incidence of RSV-related Lower Respiratory Tract Disease (LRTD) hospitalization
Time frame: up to 3 years
2 secondary outcomes
Incidence of RSV-related outcomes
Time frame: up to 3 years
Incidence of All-cause outcomes
Time frame: up to 3 years
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Aug 2026.
- Individual participant dataSharing planned: No. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Respiratory Syncytial Virus (RSV), run by Pfizer at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 20 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of RSV-related Acute Respiratory Infection (ARI) hospitalization (time frame: up to 3 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Aug 2026.