RSV ImmunizationNCT07634692
An Observational Study to Assess Nirsevimab Immunization Rates in Eligible Infants During Their First RSV Season in the Czechia
An observational study of RSV Immunization, run by Sanofi at 1 site in Czechia.
Trial summary
The primary objective of this study is to determine the nirsevimab immunization rate in eligible infants in their first RSV-season in Czechia. The study will focus on: 1. Assessing nirsevimab immunization rates among eligible infants (according to ČVS recommendation) in their first RSV-season in Czechia (i.e. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- RSV Immunization
- What is being tested?
- Nirsevimab Respiratory Syncytial Virus monoclonal antibody
- How many people
- 257 participants
- Where
- 1 siteCzechia
- Study dates
- 15 Jun 2026to 26 Jun 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
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
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study will target a sample of 250 parents of infants born between April 2025 and March 2027. Eligible participants must be at least 18, reside in Czechia at the time of survey completion and speak Czech.
Who may be able to join
- Be a parent of an infant born between April 2025/26 and March 2026/27, respectively
- Permanent residence in Czechia at the time of survey completion and speak Czech
- Be at least 18 years old at the time of survey completion
- Agree with privacy policy and AE (Adverse Event) reporting requirements before proceeding with the survey
- Read and agree to the ICF (Informed Consent Form) by ticking a box before proceeding with the survey
Who cannot join
- N/A
- The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.
Trial locations and contacts
1 site in 1 country.
About this study
The primary objective of this study is to determine the nirsevimab immunization rate in eligible infants in their first RSV-season in Czechia.
The study will focus on:
Read more
- Assessing nirsevimab immunization rates among eligible infants (according to ČVS recommendation) in their first RSV-season in Czechia (i.e. across all geographies)
- Assessing nirsevimab immunisation rates among the "catch-up cohort", i.e. all infants born between April and September.
- Assessing nirsevimab immunization rate among the "in-season cohort", i.e. all infants born during the RSV season between October and March.
Secondary objectives are:
- To analyze reasons of parents to decide for or against immunization of their infant with nirsevimab.
- To assess immunization rates for further subgroups, if sufficient sample for subgroup achieved, e.g. by: risk group (defined chronic condition or pre-term birth status)
- To assess concordance of a parent survey results based on randomly sampled parent population using Computer-Assisted Self-Interviewing (CASI) for estimating immunization rates in Czechia with coverage calculated based on pharmacy sales data.
- Conditions
- RSV Immunization
- Being tested
- Nirsevimab Respiratory Syncytial Virus monoclonal antibody
- Keywords
- nirsevimab;, nirsevimab immunization rates
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nirsevimab Respiratory Syncytial Virus monoclonal antibodyBiological
This study will not administer any treatment, only observe the treatment as prescribed in real-world clinical practice
| Study group | Role | What they receive |
|---|---|---|
| Cohort 1 | "Catch-up cohort", i.e. all infants born between April and September in Czechia. Receives: Biological: Nirsevimab Respiratory Syncytial Virus monoclonal antibody | |
| Cohort 2 | "In-season cohort", i.e. all infants born during the RSV season between October and March in Czechia. Receives: Biological: Nirsevimab Respiratory Syncytial Virus monoclonal antibody |
What is being measured
The primary outcome is the main question the study is designed to answer.
The proportion of immunised infants among all enrolled infants
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Measured: June 2026 - July 2026
Type of immunisation
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Measured: June 2026 - July 2026
Location of immunization
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Measured: June 2026 - July 2026
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jun 2026
- Study start15 Jun 2026
- Primary completion26 Jun 2026
- Study completion26 Jun 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for RSV ImmunizationStudies of the same condition, open and under way.
- More trials run by SanofiThe 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
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 257 participants (actual)
Sponsor and investigators
- Lead sponsor
- Sanofi
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07634692
- Sponsor's protocol ID
- RSV25849
- Other IDs
- U1111-1342-0595
- Status last verified
- Aug 2026
- First submitted
- 3 Jun 2026
- Last updated
- 10 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
Study at a glance
From the registry record, last updated by the sponsor on 10 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Observational Study to Assess Nirsevimab Immunization Rates in Eligible Infants During Their First RSV Season in the Czechia
- ClinicalTrials.gov ID
- NCT07634692
- Acronym / sponsor ID
- RSV25849
- Conditions
- RSV Immunization
- Keywords
- nirsevimab;, nirsevimab immunization rates
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 257 participants (actual)
- Lead sponsor
- SanofiIndustry (pharma, biotech, devices)
- Study start
- 15 Jun 2026 (actual)
- Primary completion
- 26 Jun 2026 (actual)
- Study completion
- 26 Jun 2026 (actual)
- First posted
- 9 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.
The primary objective of this study is to determine the nirsevimab immunization rate in eligible infants in their first RSV-season in Czechia.
The study will focus on:
- Assessing nirsevimab immunization rates among eligible infants (according to ČVS recommendation) in their first RSV-season in Czechia (i.e. across all geographies)
- Assessing nirsevimab immunisation rates among the "catch-up cohort", i.e. all infants born between April and September.
- Assessing nirsevimab immunization rate among the "in-season cohort", i.e. all infants born during the RSV season between October and March.
Secondary objectives are:
- To analyze reasons of parents to decide for or against immunization of their infant with nirsevimab.
- To assess immunization rates for further subgroups, if sufficient sample for subgroup achieved, e.g. by: risk group (defined chronic condition or pre-term birth status)
- To assess concordance of a parent survey results based on randomly sampled parent population using Computer-Assisted Self-Interviewing (CASI) for estimating immunization rates in Czechia with coverage calculated based on pharmacy sales data.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Cohort 1 | – | Biological: Nirsevimab Respiratory Syncytial Virus monoclonal antibody"Catch-up cohort", i.e. all infants born between April and September in Czechia. |
| Cohort 2 | – | Biological: Nirsevimab Respiratory Syncytial Virus monoclonal antibody"In-season cohort", i.e. all infants born during the RSV season between October and March in Czechia. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study will target a sample of 250 parents of infants born between April 2025 and March 2027. Eligible participants must be at least 18, reside in Czechia at the time of survey completion and speak Czech.
Key inclusion criteria (5 listed)
- Be a parent of an infant born between April 2025/26 and March 2026/27, respectively
- Permanent residence in Czechia at the time of survey completion and speak Czech
- Be at least 18 years old at the time of survey completion
- Agree with privacy policy and AE (Adverse Event) reporting requirements before proceeding with the survey
- Read and agree to the ICF (Informed Consent Form) by ticking a box before proceeding with the survey
Key exclusion criteria (2 listed)
- N/A
- The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Nirsevimab Respiratory Syncytial Virus monoclonal antibodyThis study will not administer any treatment, only observe the treatment as prescribed in real-world clinical practice | Biological | Cohort 1, Cohort 2 |
Primary outcome
The proportion of immunised infants among all enrolled infants
Time frame: June 2026 - July 2026
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Type of immunisation
Time frame: June 2026 - July 2026
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Location of immunization
Time frame: June 2026 - July 2026
A descriptive analysis of immunisation status (yes/no) will be performed using summary statistics.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Aug 2026.
- Individual participant dataSharing planned: Yes. Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org
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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.
The record lists no contact. Use the official record to reach the sponsor.
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 RSV Immunization, run by Sanofi at 1 site in Czechia.
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 5 inclusion and 2 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: finished, as of the sponsor's last update on 10 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 Czechia. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
The proportion of immunised infants among all enrolled infants (time frame: June 2026 - July 2026). The study lists 3 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 10 Aug 2026; AzTrials last refreshed its copy on 26 Oct 2026.