Immunogenicity Study of an Inactivated Influenza Vaccine (Split Virus, Vero Cell Derived) to Prevent Culture Confirmed Influenza Infection

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.

Study Overview

• Status: Completed
• Conditions: Influenza
• Intervention / Treatment: Biological: Vero cell-derived, trivalent, seasonal influenza vaccine; Biological: Placebo: Phosphate-buffered saline

• Study Type: Interventional
• Enrollment (Actual): 7250
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Tucson, Arizona, United States, 85712
      • Quality of Life Medical & Research Center, LLC
  • California
    • Sacramento, California, United States, 95816
      • Benchmark Research
    • San Diego, California, United States, 92103
      • California Research Foundation
    • San Francisco, California, United States, 94102
      • Benchmark Research San Francisco
  • Colorado
    • Denver, Colorado, United States, 80239
      • Radiant Research, Inc
  • Florida
    • Coral Gables, Florida, United States, 33134
      • Clinical Research of South Florida
    • Jacksonville, Florida, United States, 32216
      • Jacksonville Center for Clinical Research
    • Miami, Florida, United States, 33126
      • Pharmax Research Clinic
    • Pembroke Pines, Florida, United States, 33024
      • University Clinical Research, Inc
    • South Miami, Florida, United States, 33143
      • Miami Research Associates
  • Georgia
    • Stockbridge, Georgia, United States, 30281
      • Clinical Research Atlanta
  • Illinois
    • Chicago, Illinois, United States, 60654
      • Radiant Research, Inc - Chicago
  • Kansas
    • Lenexa, Kansas, United States, 66219
      • Johnson County Clin-Trials
    • Overland Park, Kansas, United States, 66212
      • Vince and Associates Clinical Research
  • Kentucky
    • Lexington, Kentucky, United States, 40509
      • Central Kentucky Research Associates, Inc.
  • Louisiana
    • Metairie, Louisiana, United States, 70006
      • Benchmark Research
  • Missouri
    • Kansas City, Missouri, United States, 64114
      • Center for Pharmaceutical Research
    • St Louis, Missouri, United States, 63141
      • Radiant Research, Inc.
    • St Louis, Missouri, United States, 63141
      • Sundance Clinical Research
  • Nebraska
    • Omaha, Nebraska, United States, 68134
      • Meridian Clinical Research, LLC
  • New York
    • Endwell, New York, United States, 13760
      • Regional Clinical Research, Inc.
    • Rochester, New York, United States, 14609
      • Rochester Clinical Research, Inc.
  • North Carolina
    • Raleigh, North Carolina, United States, 27612
      • Wake Research Associates, LLC
    • Raleigh, North Carolina, United States, 27609
      • Triangle Medical Research Associates
  • Ohio
    • Cincinnati, Ohio, United States, 45249
      • Radiant Research - Cincinnati
  • Rhode Island
    • Warwick, Rhode Island, United States, 02886
      • Omega Medical Research
  • South Carolina
    • Spartanburg, South Carolina, United States, 29303
      • Spartanburg Medical Research
  • South Dakota
    • Rapid City, South Dakota, United States, 57702
      • Health Concepts
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Clinical Research Associates, Inc. - Nashville
  • Texas
    • Austin, Texas, United States, 78705
      • Benchmark Research Austin
    • Fort Worth, Texas, United States, 76135
      • Benchmark Research Ft. Worth
    • San Angelo, Texas, United States, 76904
      • Benchmark Research San Angeolo
  • Utah
    • Salt Lake City, Utah, United States, 84124
      • Jean Brown Research / Westside Medical
    • West Jordan, Utah, United States, 84088
      • Advanced Clinical Research
  • Virginia
    • Burke, Virginia, United States, 22015
      • Pi-Coor Clinical Research
    • Norfolk, Virginia, United States, 23507
      • Clinical Research Associates of Tidewater

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 49 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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
  • 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; Vero cell-derived, trivalent, seasonal influenza vaccine	Biological: Vero cell-derived, trivalent, seasonal influenza vaccine; Single intramuscular injection
Placebo Comparator: 2; Phosphate-buffered saline	Biological: Placebo: Phosphate-buffered saline; Single intramuscular injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	180 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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	180 days
HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21		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		21 days
Fold Increase of HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21 as Compared to Baseline		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.	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	180 days
Frequency and Severity of Occurrence of Any Injection Site Reactions and Systemic AEs Observed During the Entire 180-day Follow-up Period		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	180 days

Collaborators and Investigators

• Sponsor: Alachua Government Services, Inc.
• Investigators: Study Director: Baxter Bio Science Investigator, MD, Baxter Healthcare Corporation

Study record dates

Study Major Dates

• Study Start: December 1, 2008
• Primary Completion (Actual): May 1, 2009
• Study Completion (Actual): June 1, 2009

Study Registration Dates

• First Submitted: December 1, 2008
• First Submitted That Met QC Criteria: December 1, 2008
• First Posted (Estimated): December 2, 2008

Study Record Updates

• Last Update Posted (Estimated): November 24, 2025
• Last Update Submitted That Met QC Criteria: November 12, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Orthomyxoviridae Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Influenza, Human
• Other Study ID Numbers: 720802