An observational study in Respiratory Syncytial Virus Infections, sponsored by Pfizer. Not yet recruiting. Open to participants aged 0 Years to 12 Months. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by Pfizer · Observational
Among 13 studies in Respiratory Syncytial Virus Infections by Pfizer — 2 open to participants now, 3 under way, 1 of them phase 3. Respiratory Syncytial Virus Infections · Pfizer.
Among the 13 studies in Respiratory Syncytial Virus Infections by Pfizer, this one is the only one that started in 2026, is one of 2 observational ones, and was the 13th registered.
306 studies on the registry are indexed under Respiratory Syncytial Virus Infections; 50 are open to participants now.
Browse Respiratory Syncytial Virus Infections studies →2 of the 13 studies in Respiratory Syncytial Virus Infections by Pfizer are open now, in 4 countries. Recruiting first, the newest first:
Pfizer · Sites in United States, Argentina, South Africa and 1 more country
Ages 0+ · Healthy volunteers
By country, each count listing its studies:
Of the 30 Respiratory Syncytial Virus Infections studies recruiting now, 14 (47%) set no upper age limit and 12 (40%) stop at 75 or younger; 13 take children under 18; 9 take healthy volunteers.
This study: 0 Years to 12 Months · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
13 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 6 · Phase 2 3 · Phase 3 3
First in 2017; this study’s year is marked. 1 started in 2026.
This study's planned enrollment of 1 is below the median of 375 across 76 observational studies indexed under Respiratory Syncytial Virus Infections.
Median enrollment 16 across the 11 interventional studies, 551 across the 2 observational. Of the 9 that completed or were terminated, 4 (44%) have results posted.
This tab as a report to print or save as PDF → With an account.
Pfizer is the lead sponsor of 3,337 studies on the registry; 150 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 392 (65%) have results posted.
2 of the studies in Respiratory Syncytial Virus Infections by Pfizer that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT07235397PfizerEvaluating the Benefits of RSV Maternal Vaccination Using a Scottish National Dataset | 2026-11-13 |
| NCT06546800PfizerSPECIAL INVESTIGATION FOR ABRYSVO IN INDIVIDUALS AGED 60 YEARS OR OLDER | 2027-10-28 |
Add all 2 to your calendar (.ics) → With an account.
Among the 13 studies in Respiratory Syncytial Virus Infections by Pfizer, from their registry updates:
Nothing recorded among them since 2026-09-25.
This tab as a report to print or save as PDF → With an account.
This study will use a retrospective cohort design and will be conducted within routinely collected national healthcare and statutory demographic datasets held by PHS and National Records of Scotland (NRS). As such, there will be no active enrollment of study participants, no direct contact with study participants, no collection of any primary data outside of the standard of care (SOC), and no requirement for informed consent.
This study design was chosen due to several advantages, over other possible designs, including the ability to evaluate incidence of study outcomes in exposed and unexposed infants, ability to follow infants longitudinally to evaluate study outcomes through 12 months of age, and ability to evaluate all-cause outcomes.
Study endpoints, including RSV-associated LRTD hospitalization and RSV-associated hospitalization, among infants born to ABRYSVO-vaccinated mothers (exposed group) will be compared with those among infants born to ABRYSVO-unvaccinated mothers (comparison group) initially from birth through 6 months of age, with later analysis from birth through 12 months as the infants reach this age threshold and their data become available.
This will be a whole population birth cohort study of all live-born infants born in Scotland during the study period. In Scotland, all infants are assigned a unique identifier, the Community Health Index (CHI) at birth. CHI is a common identifier across all National Health Service (NHS) healthcare encounters and allows linkage of all healthcare data to statutory datasets such as death records. The patient population will include all live-born infants born in Scotland over an 18-month accrual period, from 1st September 2024 - 28th February 2026 (or end of RSV season) and their mothers (approximately 69,000 mother-infant pairs). Selection criteria for the population were based on the time period of the RSV season in Scotland and the earliest gestational age eligible for ABRYSVO vaccination, per the MHRA. All infants will be followed for 12 months after birth; thus, the last outcome assessment will be approximately 28th February 2027.
Infants must meet all inclusion criteria to be eligible for inclusion in the study:
Infants meeting any of the following criteria will not be included in the study:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Infants whose mother received ABRYSVO vaccine during pregnancy 14 days or more before delivery
Biological: ABRYSVO
Infants born to mothers who did not receive ABRYSVO during pregnancy will be considered unexposed
ABRYSVO
PCR-confirmed RSV-associated LRTD hospitalization occurring ≤180 days after birth (first episode)
Time frame: ≤180 days after birth
PCR-confirmed RSV-associated hospitalization occurring ≤180 days after birth (first episode)
Time frame: ≤180 days after birth
PCR-confirmed RSV-associated LRTD hospitalization occurring ≤180 days after birth (first episode) stratified by term/preterm status and by gestational age at vaccination
Time frame: ≤180 days after birth
PCR-confirmed RSV-associated hospitalization occurring ≤180 days after birth (first episode) stratified by term/preterm status at delivery and by gestational age at vaccination
Time frame: ≤180 days after birth
PCR-confirmed RSV-associated LRTD hospitalization occurring ≤360 days after birth (first episode) (by cumulative and by discrete age-intervals)
Time frame: ≤360 days after birth
PCR-confirmed RSV-associated hospitalization occurring ≤360 days after birth (first episode) (by cumulative and by discrete age-intervals)
Time frame: ≤360 days after birth
LRTI hospitalization (any cause) occurring ≤360 days after birth (first episode during the RSV season) (cumulative and by age-intervals)
Time frame: ≤360 days after birth
ARI hospitalization (any cause) occurring ≤360 days after birth (first episode during the RSV season) (cumulative and by age-intervals)
Time frame: ≤360 days after birth
PCR-confirmed RSV-associated hospitalization stratified by: gestational age (GA) at delivery, GA at vaccination, time from vaccination to birth, with/without administration with other maternal vaccines, breastfeeding status & infant deprivation index
Time frame: ≤360 days after birth
Infant & hospitalization characteristics (e.g. infant age at hospitalization, duration of stay in days, level of care, disease severity, death) among infants ≤360 days after birth with RSV-associated hospitalization & maternal ABYRSVO vaccination status
Time frame: ≤360 days after birth
Relative risk of breakthrough RSV in infants born to mothers vaccinated with ABRYSVO by sex, gestational age at birth, low birth weight, deprivation index, ethnicity, time between vaccine and delivery, and maternal morbidity status.
Time frame: ≤360 days after birth
No study locations are listed for this record.
Plan to share: 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.
No publications or documents are linked to this record.
Start is estimated for Oct 2026; primary completion for Nov 2026, 0 months later.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Respiratory Syncytial Virus Infections →