InfluenzaPhase 1FLU-TWNCT03898986
The Effects of Attenuated Versus Inactivated Flu Vaccine in Twin Sets
A Phase 1 study testing Live attenuated influenza vaccine (LAIV4) and Inactivated Influenza Vaccine (IIV4) in people with Influenza, run by Stanford University at 1 site in United States.
Trial summary
This is one project of a larger ongoing study related to the immune system's response to the flu virus. This study is designed to investigate the immune response to the live attenuated influenza vaccine (LAIV) vs. the Inactivated Influenza Vaccine (IIV) in identical and fraternal twins. Read more about this study
- Who is it for?
- Ages 2 to 20 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza
- What is being tested?
- Live attenuated influenza vaccine (LAIV4) and Inactivated Influenza Vaccine (IIV4)
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 8 Oct 2019to 31 Dec 2023
- Phase
- Phase 1
- 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 2 to 20 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- 2-20 year old male and female patients
- Willing and able to complete the informed consent process
- Availability of twin pair also agreeable and eligible for study inclusion
- Availability for follow-up for the planned duration of the study
- Acceptable medical history by review of inclusion/exclusion criteria
Who cannot join
- Prior off-study vaccination with seasonal influenza vaccine within three months of study vaccination
- Life-threatening reactions to previous influenza vaccinations
- Asthma (contraindication for receipt of LAIV4)
- Allergy to egg or egg products or to vaccine components including gentamicin, gelatin, arginine or MSG.
- Active systemic or serious concurrent illness, including febrile illness on the day of vaccination
- History of immunodeficiency (including HIV infection)
Show all 27Show fewer
- Known or suspected impairment of immunologic function; may include significant liver disease, diabetes mellitus treated with insulin or moderate to severe renal disease
- Hospitalization in the past year for congestive heart failure or emphysema.
- Chronic Hepatitis B or C.
- Recent or current use of immunosuppressive medication, including systemic glucocorticoids (corticosteroid nasal sprays and topical steroids are permissible). Use of oral steroids (<20mg prednisone-equivalent/day) may be acceptable after review by the investigator.
- Participants in close contact with anyone who has a severely weakened immune system
- Malignancy, other than squamous cell or basal cell skin cancer (includes solid tumors such as breast cancer or prostate cancer with recurrence in the past year, and any hematologic cancer such as leukemia).
- Autoimmune disease (including rheumatoid arthritis treated with immunosuppressive medication such as Plaquenil, methotrexate, prednisone, Enbrel) which, in the opinion of the investigator might jeopardize volunteer safety or compliance with the protocol.
- History of blood dyscrasias, renal disease, or hemoglobinopathies requiring regular medical follow up or hospitalization during the preceding year
- Use of any anti-coagulation medication such as Coumadin or Lovenox, or anti-platelet agents such as aspirin (except up to 325 mg. per day), Plavix, or Aggrenox will be reviewed by investigators to determine if study participation would affect the volunteer's safety or compliance with the protocol.
- Has taken an influenza antiviral medication within 48 hours prior to study vaccination [If yes, may not eligible if unable to schedule at an appropriate interval].
- Receipt of blood or blood products within the past 6 months or planned used during the study.
- Medical or psychiatric condition or occupational responsibilities that preclude participant compliance with the protocol
- Receipt of an inactivated vaccine 14 days prior to study enrollment, or planned vaccinations prior to completion of last study visit (~ 14 days after study vaccination)
- Receipt of a live, attenuated vaccine within 60 days prior to enrollment of planned vaccination prior to completion of last study visit (~ 14 days after study enrollment)
- Need for allergy immunization (that cannot be postponed) until after the last study visit.
- History of Guillain-Barre# syndrome
- Pregnant woman
- Breastfeeding woman
- Use of investigational agents within 30 days prior to enrollment or planned use during the study.
- Donation of the equivalent of a unit of blood within 6 weeks prior to enrollment or donation of platelets within 2 weeks of enrollment or planned donation prior to completion of the last visit.
- Any condition which, in the opinion of the investigator, might interfere with volunteer safety, study objectives or the ability of the participant to understand or comply with the study protocol.
Trial locations and contacts
1 site in 1 country.
United States1 site
Stanford University School of Medicine
Stanford, California, 94305
About this study
This is one project of a larger ongoing study related to the immune system's response to the flu virus. This study is designed to investigate the immune response to the live attenuated influenza vaccine (LAIV) vs. the Inactivated Influenza Vaccine (IIV) in identical and fraternal twins.
Read the detailed description
This is a Phase I mechanistic study of licensed influenza vaccines. The study requires 10 monozygotic and 10 dizygotic sets of twins (40 total participants) to enroll.
The duration of the study for an individual volunteer will be 4 weeks including screening and active participation. The study has a total of 3 visits.
First visit: Procedures during this visit are: Informed consent process, enrollment, study assessments, 20 ml blood draw, and vaccination. Participants will be randomized to receive either LAIV or IIV.
The time required to complete the first study visit will be about 30-40 minutes.
2nd (day 7 post vaccination) and 3rd (day 28 post vaccination ) visit: 20 ml blood will be obtained and the visit will take approximately 15 minutes.
- Conditions
- Influenza
- Being tested
- Live attenuated influenza vaccine (LAIV4), Inactivated Influenza Vaccine (IIV4)
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Live attenuated influenza vaccine (LAIV4)Biological
Also called FluMist® Quadrivalent
LAIV4 vaccine dosage is 0.2 mL. The vaccine will be administered as an intranasal spray. Each sprayer contains a single dose of FluMist® Quadrivalent; approximately one-half of the contents should be administered into each nostril. 0.1 mL (i.e., half of the dose from a single FluMist sprayer) is administered into each nostril while the recipient is in an upright position. Insert the tip of the sprayer just inside the nose and rapidly depress the plunger until the dose-divider clip stops the plunger. The dose-divider clip is removed from the sprayer to administer the second half of the dose (0.1 mL) into the other nostril.
Inactivated Influenza Vaccine (IIV4)Biological
Also called Fluzone® Quadrivalent vaccine
IIV4 vaccine will be administered as a 0.5 mL dose, with a sterile, disposable syringe and needle by IM injection.
| Study group | Role | What they receive |
|---|---|---|
| MZ twins (IIV or LAIV4) | Experimental | Up to 20 healthy monozygotic (MZ) individual twin volunteers, 2-20 years old, will be randomized within the twin pair to receive either inactivated influenza vaccine quadrivalent (IIV4) Fluzone® Quadrivalent vaccine or live, attenuated influenza vaccine quadrivalent (LAIV4) FluMist® Quadrivalent. Each volunteer will complete a total of 3 visits: Day 0 (pre-immunization), Day 7 and Day 28 post-immunization. All visits will consist of drawing blood for study assays and monitoring for serious adverse events (SAEs). Receives: Biological: Live attenuated influenza vaccine (LAIV4); Biological: Inactivated Influenza Vaccine (IIV4) |
| DZ twins (IIV or LAIV4) | Experimental | Up to 20 healthy dizygotic (DZ) individual twin volunteers, 2-20 years old, will be randomized within the twin pair to receive either inactivated influenza vaccine quadrivalent (IIV4) Fluzone® Quadrivalent vaccine or live, attenuated influenza vaccine quadrivalent (LAIV4) FluMist® Quadrivalent. Each volunteer will complete a total of 3 visits: Day 0 (pre-immunization), Day 7 and Day 28 post-immunization. All visits will consist of drawing blood for study assays and monitoring for serious adverse events (SAEs). Receives: Biological: Live attenuated influenza vaccine (LAIV4); Biological: Inactivated Influenza Vaccine (IIV4) |
What is being measured
The primary outcome is the main question the study is designed to answer.
HAI Titers
Evaluate HAI titers in response to influenza vaccination. An HAI titer is a hemoglobin assay that correlates to protection from influenza infection; an HAI titer of 40 or greater is considered to be protective.
Measured: Day 28
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Apr 2019
- Study start8 Oct 2019
- Primary completion31 Dec 2023
- Study completion31 Dec 2023
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 InfluenzaStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe 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
- Interventional
- Phase
- Phase 1
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID)
- Responsible party
- Principal investigator, Philip Grant, Stanford University
- Investigators
- Philip M Grant, Principal investigator, Assistant Professor of Medicine (Infectious Diseases)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03898986
- Sponsor's protocol ID
- 50200
- Other IDs
- 5U19AI057229-15
- Acronym
- FLU-TW
- Status last verified
- Feb 2025
- First submitted
- 30 Mar 2019
- Last updated
- 6 Mar 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Attenuated Versus Inactivated Flu Vaccine in Twin Sets
- ClinicalTrials.gov ID
- NCT03898986
- Acronym / sponsor ID
- FLU-TW / 50200
- Conditions
- Influenza
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID)
- Study start
- 8 Oct 2019 (actual)
- Primary completion
- 31 Dec 2023 (actual)
- Study completion
- 31 Dec 2023 (actual)
- First posted
- 2 Apr 2019 (actual)
- Results
- Posted 6 Mar 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is one project of a larger ongoing study related to the immune system's response to the flu virus. This study is designed to investigate the immune response to the live attenuated influenza vaccine (LAIV) vs. the Inactivated Influenza Vaccine (IIV) in identical and fraternal twins.
Detailed description
This is a Phase I mechanistic study of licensed influenza vaccines. The study requires 10 monozygotic and 10 dizygotic sets of twins (40 total participants) to enroll.
The duration of the study for an individual volunteer will be 4 weeks including screening and active participation. The study has a total of 3 visits.
First visit: Procedures during this visit are: Informed consent process, enrollment, study assessments, 20 ml blood draw, and vaccination. Participants will be randomized to receive either LAIV or IIV.
The time required to complete the first study visit will be about 30-40 minutes.
2nd (day 7 post vaccination) and 3rd (day 28 post vaccination ) visit: 20 ml blood will be obtained and the visit will take approximately 15 minutes.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| MZ twins (IIV or LAIV4) | Experimental | Biological: Live attenuated influenza vaccine (LAIV4), Biological: Inactivated Influenza Vaccine (IIV4)Up to 20 healthy monozygotic (MZ) individual twin volunteers, 2-20 years old, will be randomized within the twin pair to receive either inactivated influenza vaccine quadrivalent (IIV4) Fluzone® Quadrivalent vaccine or live, attenuated influenza vaccine quadrivalent (LAIV4) FluMist® Quadrivalent. Each volunteer will complete a total of 3 visits: Day 0 (pre-immunization), Day 7 and Day 28 post-immunization. All visits will consist of drawing blood for study assays and monitoring for serious adverse events (SAEs). |
| DZ twins (IIV or LAIV4) | Experimental | Biological: Live attenuated influenza vaccine (LAIV4), Biological: Inactivated Influenza Vaccine (IIV4)Up to 20 healthy dizygotic (DZ) individual twin volunteers, 2-20 years old, will be randomized within the twin pair to receive either inactivated influenza vaccine quadrivalent (IIV4) Fluzone® Quadrivalent vaccine or live, attenuated influenza vaccine quadrivalent (LAIV4) FluMist® Quadrivalent. Each volunteer will complete a total of 3 visits: Day 0 (pre-immunization), Day 7 and Day 28 post-immunization. All visits will consist of drawing blood for study assays and monitoring for serious adverse events (SAEs). |
Who may qualify
- Ages
- 2 to 20 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (5 listed)
- 2-20 year old male and female patients
- Willing and able to complete the informed consent process
- Availability of twin pair also agreeable and eligible for study inclusion
- Availability for follow-up for the planned duration of the study
- Acceptable medical history by review of inclusion/exclusion criteria
Key exclusion criteria (27 listed)
- Prior off-study vaccination with seasonal influenza vaccine within three months of study vaccination
- Life-threatening reactions to previous influenza vaccinations
- Asthma (contraindication for receipt of LAIV4)
- Allergy to egg or egg products or to vaccine components including gentamicin, gelatin, arginine or MSG.
- Active systemic or serious concurrent illness, including febrile illness on the day of vaccination
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 |
|---|---|---|
| Live attenuated influenza vaccine (LAIV4)Also: FluMist® QuadrivalentLAIV4 vaccine dosage is 0.2 mL. The vaccine will be administered as an intranasal spray. Each sprayer contains a single dose of FluMist® Quadrivalent; approximately one-half of the contents should be administered into each nostril. 0.1 mL (i.e., half of the dose from a single FluMist sprayer) is administered into each nostril while the recipient is in an upright position. Insert the tip of the sprayer just inside the nose and rapidly depress the plunger until the dose-divider clip stops the plunger. The dose-divider clip is removed from the sprayer to administer the second half of the dose (0.1 mL) into the other nostril. | Biological | DZ twins (IIV or LAIV4), MZ twins (IIV or LAIV4) |
| Inactivated Influenza Vaccine (IIV4)Also: Fluzone® Quadrivalent vaccineIIV4 vaccine will be administered as a 0.5 mL dose, with a sterile, disposable syringe and needle by IM injection. | Biological | DZ twins (IIV or LAIV4), MZ twins (IIV or LAIV4) |
Primary outcome
HAI Titers
Time frame: Day 28
Evaluate HAI titers in response to influenza vaccination. An HAI titer is a hemoglobin assay that correlates to protection from influenza infection; an HAI titer of 40 or greater is considered to be protective.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Mar 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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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.
Philip M Grant principal investigator
Assistant Professor of Medicine (Infectious Diseases)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Live attenuated influenza vaccine (LAIV4) and Inactivated Influenza Vaccine (IIV4) in people with Influenza, run by Stanford University 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 5 inclusion and 27 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 6 Mar 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 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.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 6 Mar 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?
HAI Titers (time frame: Day 28). 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 6 Mar 2025; AzTrials last refreshed its copy on 8 Nov 2026.