InfluenzaPhase 3NCT00800605
Immunogenicity Study of an Inactivated Influenza Vaccine (Split Virus, Vero Cell Derived) to Prevent Culture Confirmed Influenza Infection
A Phase 3 study testing Vero cell-derived, trivalent, seasonal influenza vaccine in people with Influenza, run by Alachua Government Services, Inc. at 36 sites in United States.
Trial summary
The purpose of this study is to demonstrate the efficacy of an investigational Vero cell-derived, trivalent, seasonal influenza vaccine to prevent infection with an influenza virus that is antigenically similar to one of the three strains in the vaccine. Read more about this study
- Who is it for?
- Ages 18 to 49 yearsHealthy volunteers can take part
- Conditions the study is for
- Influenza
- What is being tested?
- Vero cell-derived, trivalent, seasonal influenza vaccine
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 7,250 participants
- Where
- 36 sitesUnited States
- Study dates
- Dec 2008to Jun 2009
- Phase
- Phase 3
- 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 18 to 49 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Subject has an understanding of the study
- Subject agrees to study provisions
- Subject gives written informed consent prior to study entry
- Subject is accessible by telephone or electronic mail to receive reminders from the study site
- If female and capable of bearing children, subject has a negative urine pregnancy test result within 24 hours of the vaccination on Study Day 0 and agrees to employ adequate birth control measures through the first 60 post-vaccination days.
Who cannot join
- Subject has any of the risk factors for complications from influenza infection as defined by the Centers for Disease Control and Prevention (CDC, 2008a):
- Pregnancy
- Chronic disorders of the pulmonary or cardiovascular system including asthma (hypertension is not considered a high risk condition)
- Chronic renal disorders
- Chronic hepatic disorders
- Chronic hematological disorders
Show all 23Show fewer
- Chronic metabolic disorder (including diabetes mellitus and thyroid disorders)
- Immunosuppression (including immunosuppression caused by medications, congenital etiologies or HIV)
- Any condition that can compromise respiratory function or the handling of respiratory secretions or that can increase risk for aspiration (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders or other neuromuscular disorders)
- Residence in nursing home or other chronic care facility that houses persons of any age who have chronic medical conditions
- Household contact with children aged 0 to 59 months or of someone who is included in the risk categories listed above
- Employment as a health care worker
- Subject is unable to lead an independent life as a result of either physical or mental handicap
- Subject has a history of severe allergic reactions or anaphylaxis (e.g., urticaria or asthma that is clinically severe)
- Subject has an oral temperature of >= 99.5° F (37.5°C) on the day of vaccination in this study. [NOTE: A subject meeting this exclusion criterion may be rescheduled for vaccination and study entry at a later date provided that certain requirements [in the study protocol] are met)
- Subject has a rash or dermatologic condition or tattoos which may interfere with injection site reaction rating
- Subject has received a blood transfusion, blood products or immunoglobulins within 90 days of study entry
- Subject has received a live vaccine within 4 weeks or inactivated or subunit vaccine within 2 weeks of study entry
- Subject has previously been vaccinated against influenza for the 2008/2009 northern hemisphere influenza season
- Subject has a functional or surgical asplenia
- Subject has a known or suspected problem with alcohol or drug abuse;
- Subject was administered an investigational drug within six weeks prior to study entry or are concurrently participating in a clinical study that includes the administration of an investigational product
- Subject is a member of the team conducting this study or are in a dependent relationship with the study investigator. Dependent relationships include close relatives (i.e., children, spouse/partner, siblings, parents) as well as employees of the investigator
Trial locations and contacts
36 sites in 1 country.
36 sites in 1 country
United States36 sites
Benchmark Research Austin
Austin, Texas, 78705
PI-COOR Clinical Research
Burke, Virginia, 22015
Radiant Research, Inc - Chicago
Chicago, Illinois, 60654
Radiant Research - Cincinnati
Cincinnati, Ohio, 45249
Clinical Research of South Florida
Coral Gables, Florida, 33134
Radiant Research, Inc
Denver, Colorado, 80239
Regional Clinical Research, Inc.
Endwell, New York, 13760
Benchmark Research Ft. Worth
Fort Worth, Texas, 76135
Jacksonville Center for Clinical Research
Jacksonville, Florida, 32216
Center for Pharmaceutical Research
Kansas City, Missouri, 64114
Johnson County Clin-Trials
Lenexa, Kansas, 66219
Central Kentucky Research Associates, Inc.
Lexington, Kentucky, 40509
Benchmark Research
Metairie, Louisiana, 70006
Pharmax Research Clinic
Miami, Florida, 33126
Clinical Research Associates, Inc. - Nashville
Nashville, Tennessee, 37203
Clinical Research Associates of Tidewater
Norfolk, Virginia, 23507
Meridian Clinical Research, LLC
Omaha, Nebraska, 68134
Vince and Associates Clinical Research
Overland Park, Kansas, 66212
University Clinical Research, Inc
Pembroke Pines, Florida, 33024
Triangle Medical Research Associates
Raleigh, North Carolina, 27609
Wake Research Associates, LLC
Raleigh, North Carolina, 27612
Health Concepts
Rapid City, South Dakota, 57702
Rochester Clinical Research, Inc.
Rochester, New York, 14609
Benchmark Research
Sacramento, California, 95816
Jean Brown Research / Westside Medical
Salt Lake City, Utah, 84124
Benchmark Research San Angeolo
San Angelo, Texas, 76904
California Research Foundation
San Diego, California, 92103
Benchmark Research San Francisco
San Francisco, California, 94102
Miami Research Associates
South Miami, Florida, 33143
Spartanburg Medical Research
Spartanburg, South Carolina, 29303
Radiant Research, Inc.
St Louis, Missouri, 63141
Sundance Clinical Research
St Louis, Missouri, 63141
Clinical Research Atlanta
Stockbridge, Georgia, 30281
Quality of Life Medical & Research Center, LLC
Tucson, Arizona, 85712
Omega Medical Research
Warwick, Rhode Island, 02886
Advanced Clinical Research
West Jordan, Utah, 84088
About this study
Official title: Double Blind, Placebo Controlled Phase 3 Study of the Efficacy of an Investigational Vero Cell-Derived Influenza Vaccine to Prevent Culture Confirmed Influenza Infection
The purpose of this study is to demonstrate the efficacy of an investigational Vero cell-derived, trivalent, seasonal influenza vaccine to prevent infection with an influenza virus that is antigenically similar to one of the three strains in the vaccine. Subjects will be randomized in a double-blind fashion to receive a single intramuscular injection of either the investigational vaccine or placebo. Blood will be drawn from all subjects for a determination of hemagglutination inhibition antibody titers on Days 0 and 21, body temperature and injection site reactions will be monitored daily for 7 days. In addition, subjects must return to the clinic promptly to have swab samples of their nose and throat taken whenever they feel flu symptoms and all subjects will be monitored for adverse events until Day 180.
- Conditions
- Influenza
- Being tested
- Vero cell-derived, trivalent, seasonal influenza vaccine, Placebo: Phosphate-buffered saline
- Medical subject headings
- Influenza, Human
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vero cell-derived, trivalent, seasonal influenza vaccineBiological
Single intramuscular injection
Placebo: Phosphate-buffered salineBiological
Single intramuscular injection
| Study group | Role | What they receive |
|---|---|---|
| 1 | Experimental | Vero cell-derived, trivalent, seasonal influenza vaccine Receives: Biological: Vero cell-derived, trivalent, seasonal influenza vaccine |
| 2 | Placebo comparator | Phosphate-buffered saline Receives: Biological: Placebo: Phosphate-buffered saline |
What is being measured
The primary outcome is the main question the study is designed to answer.
Efficacy of an Investigational Vero Cell-derived Influenza Vaccine to Prevent Infection With an Influenza Virus That is Antigenically Similar to One of the Three Strains in the Vaccine
The number of subjects developing influenza infection, as confirmed by viral culture and typing of naso-pharyngeal specimens, with a virus that is antigenically similar to one of the strains contained in the vaccine 21 days to 180 days after the date of vaccination.
Measured: 180 days
Secondary outcomes (9)
Number of Subjects Who Developed Influenza Infection 21 Days to 180 Days Post-vaccination With Infecting Strain Matching the Strains Contained in the Vaccine
Number of subjects with influenza infection confirmed by viral culture and typing and/or RT-PCR analysis of naso-pharyngeal specimens that are antigenically similar to the strains contained in the vaccine
Measured: 180 days
Number of Subjects Who Developed Influenza Infection Between 21 and 180 Days Post-vaccination, Regardless of Whether the Infecting Strain Matched the Vaccine Strains Antigenically
Number of subjects with influenza infection as confirmed by viral culture and typing of naso-pharyngeal specimens regardless of whether the isolate is antigenically matched to the strains contained in the vaccine
Measured: 180 days
HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21
Measured: 21 days
Percentage of Subjects With Seroprotective Antibody Titer [Reciprocal HIA Titer ≥ 40] for Each of the Three Antigens Contained in the Vaccine at Day 21
Measured: 21 days
Fold Increase of HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21 as Compared to Baseline
Measured: 21 days
Percentage of Subjects Demonstrating Seroconversion to Each of the Three Antigens Contained in the Vaccine at Day 21
Seroconversion is defined as a ≥ 4-fold increase in HIA titer from baseline or a HIA titer ≥ 40 when there is no detectable HIA titer (HIA titer <10) at baseline.
Measured: 21 days
Frequency and Severity of Occurrence of Any Injection Site Reactions Related to Vaccination
Number of Subjects With Non-Serious Local Reactions During the Entire Follow-Up Period
Measured: 180 days
Frequency and Severity of Occurrence of Any Injection Site Reactions and Systemic AEs Observed During the Entire 180-day Follow-up Period
Measured: 180 days
Frequency and Severity of Occurrence of Any Systemic Reactions Related to Vaccination
Number of Subjects With Non-Serious Systemic Reactions During the Entire Follow-Up Period
Measured: 180 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Dec 2008 (estimated)
- Study startDec 2008
- Primary completionMay 2009
- Study completionJun 2009
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.
- 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 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 7,250 participants (actual)
Sponsor and investigators
- Lead sponsor
- Alachua Government Services, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Baxter Bio Science Investigator, MD, Study director, Baxter Healthcare Corporation
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00800605
- Sponsor's protocol ID
- 720802
- Status last verified
- Nov 2025
- First submitted
- 1 Dec 2008
- Last updated
- 24 Nov 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 24 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Double Blind, Placebo Controlled Phase 3 Study of the Efficacy of an Investigational Vero Cell-Derived Influenza Vaccine to Prevent Culture Confirmed Influenza Infection
- ClinicalTrials.gov ID
- NCT00800605
- Acronym / sponsor ID
- 720802
- Conditions
- Influenza
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 7,250 participants (actual)
- Lead sponsor
- Alachua Government Services, Inc.Industry (pharma, biotech, devices)
- Study start
- Dec 2008
- Primary completion
- May 2009 (actual)
- Study completion
- Jun 2009 (actual)
- First posted
- 2 Dec 2008 (estimated)
- Results
- Posted 24 Nov 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 study is to demonstrate the efficacy of an investigational Vero cell-derived, trivalent, seasonal influenza vaccine to prevent infection with an influenza virus that is antigenically similar to one of the three strains in the vaccine. Subjects will be randomized in a double-blind fashion to receive a single intramuscular injection of either the investigational vaccine or placebo. Blood will be drawn from all subjects for a determination of hemagglutination inhibition antibody titers on Days 0 and 21, body temperature and injection site reactions will be monitored daily for 7 days. In addition, subjects must return to the clinic promptly to have swab samples of their nose and throat taken whenever they feel flu symptoms and all subjects will be monitored for adverse events until Day 180.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 1 | Experimental | Biological: Vero cell-derived, trivalent, seasonal influenza vaccineVero cell-derived, trivalent, seasonal influenza vaccine |
| 2 | Placebo comparator | Biological: Placebo: Phosphate-buffered salinePhosphate-buffered saline |
Who may qualify
- Ages
- 18 to 49 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Subject has an understanding of the study
- Subject agrees to study provisions
- Subject gives written informed consent prior to study entry
- Subject is accessible by telephone or electronic mail to receive reminders from the study site
- If female and capable of bearing children, subject has a negative urine pregnancy test result within 24 hours of the vaccination on Study Day 0 and agrees to employ adequate birth control measures through the first 60 post-vaccination days.
Key exclusion criteria (23 listed)
- Subject has any of the risk factors for complications from influenza infection as defined by the Centers for Disease Control and Prevention (CDC, 2008a):
- Subject is unable to lead an independent life as a result of either physical or mental handicap
- Subject has a history of severe allergic reactions or anaphylaxis (e.g., urticaria or asthma that is clinically severe)
- Subject has an oral temperature of >= 99.5° F (37.5°C) on the day of vaccination in this study. [NOTE: A subject meeting this exclusion criterion may be rescheduled for vaccination and study entry at a later date provided that certain requirements [in the study protocol] are met)
- Subject has a rash or dermatologic condition or tattoos which may interfere with injection site reaction rating
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 |
|---|---|---|
| Vero cell-derived, trivalent, seasonal influenza vaccineSingle intramuscular injection | Biological | 1 |
| Placebo: Phosphate-buffered salineSingle intramuscular injection | Biological | 2 |
Primary outcome
Efficacy of an Investigational Vero Cell-derived Influenza Vaccine to Prevent Infection With an Influenza Virus That is Antigenically Similar to One of the Three Strains in the Vaccine
Time frame: 180 days
The number of subjects developing influenza infection, as confirmed by viral culture and typing of naso-pharyngeal specimens, with a virus that is antigenically similar to one of the strains contained in the vaccine 21 days to 180 days after the date of vaccination.
9 secondary outcomes
Number of Subjects Who Developed Influenza Infection 21 Days to 180 Days Post-vaccination With Infecting Strain Matching the Strains Contained in the Vaccine
Time frame: 180 days
Number of Subjects Who Developed Influenza Infection Between 21 and 180 Days Post-vaccination, Regardless of Whether the Infecting Strain Matched the Vaccine Strains Antigenically
Time frame: 180 days
HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21
Time frame: 21 days
Percentage of Subjects With Seroprotective Antibody Titer [Reciprocal HIA Titer ≥ 40] for Each of the Three Antigens Contained in the Vaccine at Day 21
Time frame: 21 days
Fold Increase of HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21 as Compared to Baseline
Time frame: 21 days
Percentage of Subjects Demonstrating Seroconversion to Each of the Three Antigens Contained in the Vaccine at Day 21
Time frame: 21 days
Frequency and Severity of Occurrence of Any Injection Site Reactions Related to Vaccination
Time frame: 180 days
Frequency and Severity of Occurrence of Any Injection Site Reactions and Systemic AEs Observed During the Entire 180-day Follow-up Period
Time frame: 180 days
Frequency and Severity of Occurrence of Any Systemic Reactions Related to Vaccination
Time frame: 180 days
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Nov 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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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.
Baxter Bio Science Investigator, MD study director
Baxter Healthcare Corporation
36 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Vero cell-derived, trivalent, seasonal influenza vaccine in people with Influenza, run by Alachua Government Services, Inc. at 36 sites 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 23 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 24 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 36 sites 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. Some participants in this study may receive a placebo. 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
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 24 Nov 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?
Efficacy of an Investigational Vero Cell-derived Influenza Vaccine to Prevent Infection With an Influenza Virus That is Antigenically Similar to One of the Three Strains in the Vaccine (time frame: 180 days). 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 24 Nov 2025.