Influenza ImmunityNCT04963166
Natural History of Systemic and Nasal Mucosal Immunity After Influenza Vaccination in a Pediatric Population
An observational study of Influenza Immunity, run by National Institute of Allergy and Infectious Diseases (NIAID) at 1 site in United States.
Trial summary
Background: The influenza (flu) virus infects millions around the world every year. Children are at increased risk of complications from the flu. The flu vaccine protects against influenza, but the vaccine can be improved. Read more about this study
- Who is it for?
- Ages 2 to 17 years
- Conditions the study is for
- Influenza Immunity
- How many people
- 65 participants
- Where
- 1 siteUnited States
- Study dates
- 24 Sep 2021to 20 Dec 2023
- 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 2 to 17 years
- All sexes
- No healthy volunteers
- Child
Study population: Children receiving their first ever influenza vaccine require two doses of the vaccine one month apart and will not be included in this study. Only participants who have already received a flu vaccine series in the past will be eligible for this study. Evaluation of immunity after the first ever influenza vaccination series is an important question that should be explored separately. We will enroll participants into one of three cohorts by age: 2 6 years old, 7 11 years old, and 12 17 years old. We will aim to enroll similar numbers of participants into each group to ensure a diverse age range in our population.
Who may be able to join
- In order to be eligible to enroll in this study, an individual must meet all of the following criteria:
- >= 2 years of age and < 18 years of age at the time of enrollment.
- Completed a previous influenza series in the past and therefore requires only one seasonal influenza vaccine every year.
- Planning to receive the current seasonal inactivated influenza vaccine given by injection.
- Parent or guardian willing and able to provide verbal consent.
- Willing and able to undergo home blood micro-sampling and nasal sampling.
- Willing to have samples stored for future research.
- Parent/guardian able to proficiently speak, read, and write English.
Who cannot join
- Any individual who meets any of the following criteria will be excluded from participation in this study:
- Already received the current season s influenza vaccine.
- Planning to receive the current seasonal live attenuated influenza vaccine (LAIV).
- Self-reported pregnancy or breastfeeding.
- Any condition that, in the opinion of the investigator, would compromise the safety of the study participant or staff, or would prevent proper conduct of the study.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Institute of Allergy and Infectious Diseases (NIAID)
Bethesda, Maryland, 20892
About this study
Background:
The influenza (flu) virus infects millions around the world every year. Children are at increased risk of complications from the flu. The flu vaccine protects against influenza, but the vaccine can be improved. Researchers want to learn more about children s mucosal and systemic immunity after flu vaccination. This could help to develop more effective flu vaccines in the future.
Read more
Objective:
To learn what happens in kids immune systems after receiving a flu vaccine.
Eligibility:
Children ages 2-17 who have received a flu vaccine in the past and plan to get the current seasonal flu vaccine given by injection.
Design:
All study visits will take place at home and communication with the study team will be done via phone or videoconference.
Participants will review medical history and flu vaccination history with the study team.
Participants will get the flu vaccine at their local doctor s office or pharmacy. They will not be given the vaccine in this study.
Participants will complete an electronic survey to give details about the date and type of flu vaccine received.
Participants will collect nasal and fingerstick samples at home. They will collect 4 nasal samples and 3 fingerstick samples over 6 months: once before they get the flu vaccine and 2-3 times after they get the vaccine. They will use collection kits that include instructions, sample collection supplies, and shipping materials. They will ship all samples back to NIH with all costs covered by NIH.
Participation will last for 6 months.
Compensation is provided.
Read the detailed description
Title:
Natural History of Systemic and Nasal Mucosal Immunity after Influenza Vaccination in a Pediatric Population
Study Description:
While adults are heavily represented in influenza vaccine studies, there are limited studies in the pediatric population. This study will characterize the changes in nasal and systemic immunity after influenza vaccination in a pediatric population.
Objectives:
Primary Objectives:
Characterize nasal mucosal humoral immune response pre and post influenza vaccination
Characterize systemic humoral immune response pre and post influenza vaccination
Secondary Objectives:
Describe the trend of nasal mucosal mucosal and serum humoral immune response over time after vaccination
Endpoints:
Primary Endpoints:
- Baseline and post-vaccination mucosal anti-influenza antibodies from nasal samples as measured by:
- Anti-hemagglutination (HA) head antibody quantitative enzyme-linked immunosorbent assay (ELISA) immunoglobulins (Ig) (IgA, IgG)
- Anti-HA stalk antibody quantitative ELISA (IgA, IgG)
- Anti-neuraminidase (NA) antibody quantitative ELISA (IgA, IgG)
- Baseline and post-vaccination systemic anti-influenza antibodies as measured by:
- Anti-HA head antibody quantitative ELISA (IgM, IgG, IgA)
- Anti-HA stalk antibody quantitative ELISA (IgM, IgG, IgA)
- Anti-NA antibody quantitative ELISA (IgM, IgG, IgA)
Secondary Endpoints:
Multiple timepoint measurements of mucosal anti-influenza antibodies from nasal samples as measured by:
Anti-HA head antibody quantitative ELISA (IgA, IgG)
Anti-HA stalk antibody quantitative ELISA (IgA, IgG)
Anti-NA antibody quantitative ELISA (IgA, IgG)
Multiple timepoint measurements of systemic anti-influenza antibodies as measured by:
Anti-HA head antibody quantitative ELISA (IgM, IgG, IgA)
Anti-HA stalk antibody quantitative ELISA (IgM, IgG, IgA)
Anti-NA antibody quantitative ELISA (IgM, IgG, IgA)
Study Population:
Children who are >= 2 years and < 18 years of age (N = 51; accrual ceiling = 100). Participants will be enrolled by age group: 2 - 6 years old, 7 - 11 years old and 12 - 17 years old with a goal enrollment of 17 per group.
Description of Sites/Facilities Enrolling Participants:
Participants will be enrolled by telephone or videoconference, and sample collections will be done in participant homes. Recruitment will be from community pediatric clinics and self- or family referral.
Study Duration:
2 years
- Conditions
- Influenza Immunity
- Keywords
- Flu, Flu Shot, Children, Natural History
- Medical subject headings
- Influenza, Human
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 |
|---|---|---|
| 12-17 years of age | 12-17 years of age | |
| 2-6 years of age | 2-6 years of age | |
| 7-11 years of age | 7-11 years of age |
What is being measured
The primary outcome is the main question the study is designed to answer.
Baseline and post-vaccination (6 weeks) systemic anti-influenza antibodies as measured by: 1. Anti-HA head antibody quantitative ELISA IgM, IgG, IgA 2. Anti-HA stalk antibody quantitative ELISA IgM, IgG, IgA 3. Anti-NA antibody quantitative ELIS...
Systemic anti-influenza antibodies
Measured: 6 weeks
Baseline and post-vaccination (6 weeks) mucosal anti-influenza antibodies from nasal samples as measured by: 1. Anti-HA head antibody quantitative ELISA IgA, IgG 2. Anti-HA stalk antibody quantitative ELISA IgA IgG 3. Anti-NA antibody quantitati...
Mucosal anti-influenza antibodies
Measured: 6 weeks
Secondary outcomes (2)
post-vaccination systemic anti-influenza antibodies
Systemic anti-influenza antibodies
Measured: 24 weeks
post-vaccination mucosal anti-influenza antibodies
Mucosal anti-influenza antibodies
Measured: 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jul 2021
- Study start24 Sep 2021
- Primary completion22 Jul 2022
- Study completion20 Dec 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Influenza ImmunityStudies of the same condition, open and under way.
- More trials run by National Institute of Allergy and Infectious Diseases (NIAID)The 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
- Prospective
- Enrolment
- 65 participants (actual)
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
- Responsible party
- Sponsor
- Investigators
- Alison Han, M.D., Principal investigator, National Institute of Allergy and Infectious Diseases (NIAID)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04963166
- Sponsor's protocol ID
- 10000488
- Other IDs
- 000488-I
- Status last verified
- 10 Sep 2025
- First submitted
- 14 Jul 2021
- Last updated
- 8 Apr 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: This is a small observational study, not an interventional trial, involving pediatric participants.
Study at a glance
From the registry record, last updated by the sponsor on 8 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Natural History of Systemic and Nasal Mucosal Immunity After Influenza Vaccination in a Pediatric Population
- ClinicalTrials.gov ID
- NCT04963166
- Acronym / sponsor ID
- 10000488
- Conditions
- Influenza Immunity
- Keywords
- Flu, Flu Shot, Children, Natural History
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 65 participants (actual)
- Lead sponsor
- National Institute of Allergy and Infectious Diseases (NIAID)US National Institutes of Health
- Study start
- 24 Sep 2021 (actual)
- Primary completion
- 22 Jul 2022 (actual)
- Study completion
- 20 Dec 2023 (actual)
- First posted
- 15 Jul 2021 (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.
Background:
The influenza (flu) virus infects millions around the world every year. Children are at increased risk of complications from the flu. The flu vaccine protects against influenza, but the vaccine can be improved. Researchers want to learn more about children s mucosal and systemic immunity after flu vaccination. This could help to develop more effective flu vaccines in the future.
Objective:
To learn what happens in kids immune systems after receiving a flu vaccine.
Eligibility:
Children ages 2-17 who have received a flu vaccine in the past and plan to get the current seasonal flu vaccine given by injection.
Design:
All study visits will take place at home and communication with the study team will be done via phone or videoconference.
Participants will review medical history and flu vaccination history with the study team.
Participants will get the flu vaccine at their local doctor s office or pharmacy. They will not be given the vaccine in this study.
Participants will complete an electronic survey to give details about the date and type of flu vaccine received.
Participants will collect nasal and fingerstick samples at home. They will collect 4 nasal samples and 3 fingerstick samples over 6 months: once before they get the flu vaccine and 2-3 times after they get the vaccine. They will use collection kits that include instructions, sample collection supplies, and shipping materials. They will ship all samples back to NIH with all costs covered by NIH.
Participation will last for 6 months.
Compensation is provided.
Detailed description
Title:
Natural History of Systemic and Nasal Mucosal Immunity after Influenza Vaccination in a Pediatric Population
Study Description:
While adults are heavily represented in influenza vaccine studies, there are limited studies in the pediatric population. This study will characterize the changes in nasal and systemic immunity after influenza vaccination in a pediatric population.
Objectives:
Primary Objectives:
Characterize nasal mucosal humoral immune response pre and post influenza vaccination
Characterize systemic humoral immune response pre and post influenza vaccination
Secondary Objectives:
Describe the trend of nasal mucosal mucosal and serum humoral immune response over time after vaccination
Endpoints:
Primary Endpoints:
- Baseline and post-vaccination mucosal anti-influenza antibodies from nasal samples as measured by:
- Anti-hemagglutination (HA) head antibody quantitative enzyme-linked immunosorbent assay (ELISA) immunoglobulins (Ig) (IgA, IgG)
- Anti-HA stalk antibody quantitative ELISA (IgA, IgG)
- Anti-neuraminidase (NA) antibody quantitative ELISA (IgA, IgG)
- Baseline and post-vaccination systemic anti-influenza antibodies as measured by:
- Anti-HA head antibody quantitative ELISA (IgM, IgG, IgA)
- Anti-HA stalk antibody quantitative ELISA (IgM, IgG, IgA)
- Anti-NA antibody quantitative ELISA (IgM, IgG, IgA)
Secondary Endpoints:
Multiple timepoint measurements of mucosal anti-influenza antibodies from nasal samples as measured by:
Anti-HA head antibody quantitative ELISA (IgA, IgG)
Anti-HA stalk antibody quantitative ELISA (IgA, IgG)
Anti-NA antibody quantitative ELISA (IgA, IgG)
Multiple timepoint measurements of systemic anti-influenza antibodies as measured by:
Anti-HA head antibody quantitative ELISA (IgM, IgG, IgA)
Anti-HA stalk antibody quantitative ELISA (IgM, IgG, IgA)
Anti-NA antibody quantitative ELISA (IgM, IgG, IgA)
Study Population:
Children who are >= 2 years and < 18 years of age (N = 51; accrual ceiling = 100). Participants will be enrolled by age group: 2 - 6 years old, 7 - 11 years old and 12 - 17 years old with a goal enrollment of 17 per group.
Description of Sites/Facilities Enrolling Participants:
Participants will be enrolled by telephone or videoconference, and sample collections will be done in participant homes. Recruitment will be from community pediatric clinics and self- or family referral.
Study Duration:
2 years
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 12-17 years of age | – | –12-17 years of age |
| 2-6 years of age | – | –2-6 years of age |
| 7-11 years of age | – | –7-11 years of age |
Who may qualify
- Ages
- 2 to 17 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
- Study population
- Children receiving their first ever influenza vaccine require two doses of the vaccine one month apart and will not be included in this study. Only participants who have already received a flu vaccine series in the past will be eligible for this study. Evaluation of immunity after the first ever influenza vaccination series is an important question that should be explored separately. We will enroll participants into one of three cohorts by age: 2 6 years old, 7 11 years old, and 12 17 years old. We will aim to enroll similar numbers of participants into each group to ensure a diverse age range in our population.
Key inclusion criteria (8 listed)
- In order to be eligible to enroll in this study, an individual must meet all of the following criteria:
- >= 2 years of age and < 18 years of age at the time of enrollment.
- Completed a previous influenza series in the past and therefore requires only one seasonal influenza vaccine every year.
- Planning to receive the current seasonal inactivated influenza vaccine given by injection.
- Parent or guardian willing and able to provide verbal consent.
Key exclusion criteria (5 listed)
- Any individual who meets any of the following criteria will be excluded from participation in this study:
- Already received the current season s influenza vaccine.
- Planning to receive the current seasonal live attenuated influenza vaccine (LAIV).
- Self-reported pregnancy or breastfeeding.
- Any condition that, in the opinion of the investigator, would compromise the safety of the study participant or staff, or would prevent proper conduct of the study.
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
Baseline and post-vaccination (6 weeks) systemic anti-influenza antibodies as measured by: 1. Anti-HA head antibody quantitative ELISA IgM, IgG, IgA 2. Anti-HA stalk antibody quantitative ELISA IgM, IgG, IgA 3. Anti-NA antibody quantitative ELIS...
Time frame: 6 weeks
Systemic anti-influenza antibodies
Baseline and post-vaccination (6 weeks) mucosal anti-influenza antibodies from nasal samples as measured by: 1. Anti-HA head antibody quantitative ELISA IgA, IgG 2. Anti-HA stalk antibody quantitative ELISA IgA IgG 3. Anti-NA antibody quantitati...
Time frame: 6 weeks
Mucosal anti-influenza antibodies
2 secondary outcomes
post-vaccination systemic anti-influenza antibodies
Time frame: 24 weeks
post-vaccination mucosal anti-influenza antibodies
Time frame: 24 weeks
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 8 Apr 2026.
- Individual participant dataSharing planned: No. This is a small observational study, not an interventional trial, involving pediatric participants.
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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.
Alison Han, M.D. principal investigator
National Institute of Allergy and Infectious Diseases (NIAID)
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 Influenza Immunity, run by National Institute of Allergy and Infectious Diseases (NIAID) 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 8 inclusion and 5 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 8 Apr 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?
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?
Baseline and post-vaccination (6 weeks) systemic anti-influenza antibodies as measured by: 1. Anti-HA head antibody quantitative ELISA IgM, IgG, IgA 2. Anti-HA stalk antibody quantitative ELISA IgM, IgG, IgA 3. Anti-NA antibody quantitative ELIS... (time frame: 6 weeks). 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 8 Apr 2026.