SARS-CoV-2NCT06130410
Special Investigation for Booster Dose of Comirnaty in Children Ages 6 Months Though 4 Years
An observational study of SARS-CoV-2 and COVID-19, run by Pfizer at 1 site in Japan.
Trial summary
The purpose of this post-marketing study is to assess the safety of Comirnaty monovalent XBB.1.5. for booster vaccination children ages 6 months though 4 years under actual use medical practice. Read more about this study
- Who is it for?
- Ages 6 months to 4 yearsHealthy volunteers can take part
- Conditions the study is for
- SARS-CoV-2, COVID-19
- What is being tested?
- COMIRNATY intramuscular injection
- Type of treatment
- Injection or infusion
- How many people
- 25 participants
- Where
- 1 siteJapan
- Study dates
- 6 Mar 2024to 26 Jul 2024
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 6 months to 4 years
- All sexes
- Healthy volunteers accepted
- Child
Study population: Children of 6 months though 4years of age, at the time of booster vaccination(4th dose)
Who may be able to join
- Children aged 6 months to 4 years at the time of the booster vaccination (4th dose) who (or whose representative) gave written consent to take part in the study.
Who cannot join
- -There are no exclusion criteria for this study.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: COMIRNATY Intramuscular Injection for 6 Months to 4 Years Old (Monovalent: Omicron XBB.1.5) Special Investigation for Booster Immunization in Children Aged 6 Months to 4 Years
The purpose of this post-marketing study is to assess the safety of Comirnaty monovalent XBB.1.5. for booster vaccination children ages 6 months though 4 years under actual use medical practice.
- Conditions
- SARS-CoV-2, COVID-19
- Being tested
- COMIRNATY intramuscular injection
- Keywords
- COVID-19, SARS-CoV-2, Children (6 months though 4 years old), RNA Vaccine, Post-Marketing Study, Pediatric
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
COMIRNATY intramuscular injectionBiological
Booster injection in the muscle, 1 dose
| Study group | Role | What they receive |
|---|---|---|
| COMIRNATY intramuscular injection for 6 months to 4 years old (monovalent, omicron XBB.1.5.) | Not described Receives: Biological: COMIRNATY intramuscular injection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Proportion of Participants With Adverse Reaction (AR)
An adverse event was defined as any untoward medical occurrence attributed to COMIRNATY intramuscular injection for 6 months to 4 years old (monovalent: Omicron XBB.1.5) in a participant who was vaccinated. The relatedness was assessed by the physician. Events for which a causal relationship with intramuscular injection could not be ruled out were handled as ARs.
Measured: For 28 days after the booster (4th) dose
Proportion of Participants With Serious Adverse Reaction (SAR)
An SAR was defined as any AR resulting in any of the following outcomes or deemed significant for any other reason: death; life-threatening; hospitalization or prolongation of existing hospitalization; persistent or significant disability/malfunction; congenital anomaly/birth defect; or other medically important events.
Measured: For 28 days after the booster (4th) dose
Proportion of Participants With Reactogenicity (≥ Grade 1) in Those Who Are Younger Than 2 Years of Age
Local reactions and systemic events recorded in the health observation diary collected by the physician from study participants were handled as reactogenicity events.
They were aggregated for the vaccinated participants by age group and grade. The results were aggregated by age group for local reactions and systemic events of grade 1 or higher.
If the participants were younger than 2 years of age on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site tenderness, redness, and injection site swelling. Systemic events: pyrexia, decreased appetite, somnolence, and irritability. If the participants were 2 years or older on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site pain, redness, and injection site swelling. Systemic events: pyrexia, vomiting, diarrhoea, headache, malaise, chills, myalgia, and arthralgia.
Measured: Within 7 days after the date of the booster (4th) dose
Proportion of Participants With Reactogenicity (≥ Grade 1) in Those Who Are Aged 2 Years or Older
Local reactions and systemic events recorded in the health observation diary collected by the physician from study participants were handled as reactogenicity events.
They were aggregated for the vaccinated participants by age group and grade. The results were aggregated by age group for local reactions and systemic events of grade 1 or higher.
If the participants were younger than 2 years of age on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site tenderness, redness, and injection site swelling. Systemic events: pyrexia, decreased appetite, somnolence, and irritability. If the participants were 2 years or older on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site pain, redness, and injection site swelling. Systemic events: pyrexia, vomiting, diarrhoea, headache, malaise, chills, myalgia, and arthralgia.
Measured: Within 7 days after the date of the booster (4th) dose
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Nov 2023
- Study start6 Mar 2024
- Primary completion26 Jul 2024
- Study completion26 Jul 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for SARS-CoV-2Studies 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
- Case only
- Time perspective
- Prospective
- Enrolment
- 25 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06130410
- Sponsor's protocol ID
- C4591057
- Status last verified
- Jun 2025
- First submitted
- 8 Nov 2023
- Last updated
- 14 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- 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 14 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- COMIRNATY Intramuscular Injection for 6 Months to 4 Years Old (Monovalent: Omicron XBB.1.5) Special Investigation for Booster Immunization in Children Aged 6 Months to 4 Years
- ClinicalTrials.gov ID
- NCT06130410
- Acronym / sponsor ID
- C4591057
- Conditions
- SARS-CoV-2, COVID-19
- Keywords
- COVID-19, SARS-CoV-2, Children (6 months though 4 years old), RNA Vaccine, Post-Marketing Study, Pediatric
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 25 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 6 Mar 2024 (actual)
- Primary completion
- 26 Jul 2024 (actual)
- Study completion
- 26 Jul 2024 (actual)
- First posted
- 14 Nov 2023 (actual)
- Results
- Posted 14 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this post-marketing study is to assess the safety of Comirnaty monovalent XBB.1.5. for booster vaccination children ages 6 months though 4 years under actual use medical practice.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| COMIRNATY intramuscular injection for 6 months to 4 years old (monovalent, omicron XBB.1.5.) | – | Biological: COMIRNATY intramuscular injection |
Who may qualify
- Ages
- 6 months to 4 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
- Study population
- Children of 6 months though 4years of age, at the time of booster vaccination(4th dose)
Key inclusion criteria (1 listed)
- Children aged 6 months to 4 years at the time of the booster vaccination (4th dose) who (or whose representative) gave written consent to take part in the study.
Key exclusion criteria (1 listed)
- -There are no exclusion criteria for this study.
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 |
|---|---|---|
| COMIRNATY intramuscular injectionBooster injection in the muscle, 1 dose | Biological | COMIRNATY intramuscular injection for 6 months to 4 years old (monovalent, omicron XBB.1.5.) |
Primary outcome
Proportion of Participants With Adverse Reaction (AR)
Time frame: For 28 days after the booster (4th) dose
An adverse event was defined as any untoward medical occurrence attributed to COMIRNATY intramuscular injection for 6 months to 4 years old (monovalent: Omicron XBB.1.5) in a participant who was vaccinated. The relatedness was assessed by the physician. Events for which a causal relationship with intramuscular injection could not be ruled out were handled as ARs.
Proportion of Participants With Serious Adverse Reaction (SAR)
Time frame: For 28 days after the booster (4th) dose
An SAR was defined as any AR resulting in any of the following outcomes or deemed significant for any other reason: death; life-threatening; hospitalization or prolongation of existing hospitalization; persistent or significant disability/malfunction; congenital anomaly/birth defect; or other medically important events.
Proportion of Participants With Reactogenicity (≥ Grade 1) in Those Who Are Younger Than 2 Years of Age
Time frame: Within 7 days after the date of the booster (4th) dose
Local reactions and systemic events recorded in the health observation diary collected by the physician from study participants were handled as reactogenicity events. They were aggregated for the vaccinated participants by age group and grade. The results were aggregated by age group for local reactions and systemic events of grade 1 or higher. If the participants were younger than 2 years of age on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site tenderness, redness, and injection site swelling. Systemic events: pyrexia, decreased appetite, somnolence, and irritability. If the participants were 2 years or older on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site pain, redness, and injection site swelling. Systemic events: pyrexia, vomiting, diarrhoea, headache, malaise, chills, myalgia, and arthralgia.
Proportion of Participants With Reactogenicity (≥ Grade 1) in Those Who Are Aged 2 Years or Older
Time frame: Within 7 days after the date of the booster (4th) dose
Local reactions and systemic events recorded in the health observation diary collected by the physician from study participants were handled as reactogenicity events. They were aggregated for the vaccinated participants by age group and grade. The results were aggregated by age group for local reactions and systemic events of grade 1 or higher. If the participants were younger than 2 years of age on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site tenderness, redness, and injection site swelling. Systemic events: pyrexia, decreased appetite, somnolence, and irritability. If the participants were 2 years or older on the date of the booster (4th) dose, the following reactogenicity events were aggregated. Local reactions: injection site pain, redness, and injection site swelling. Systemic events: pyrexia, vomiting, diarrhoea, headache, malaise, chills, myalgia, and arthralgia.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- 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 SARS-CoV-2 and COVID-19, run by Pfizer at 1 site in Japan.
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 1 inclusion and 1 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 14 Jul 2025. 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 Japan. 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?
Yes. Results are posted in the registry (first posted 14 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Proportion of Participants With Adverse Reaction (AR) (time frame: For 28 days after the booster (4th) dose). The study lists 4 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 14 Jul 2025.