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OpenTrials
Completed

NCT Number: NCT00800605

Immunogenicity Study of an Inactivated Influenza Vaccine (Split Virus, Vero Cell Derived) 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.

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Key information

Age range

18 year–49 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Quality of Life Medical & Research Center, LLC, Tucson, Arizona, United States

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Vero cell-derived, trivalent, seasonal influenza vaccine

Biological

Single intramuscular injection

Placebo: Phosphate-buffered saline

Biological

Single intramuscular injection

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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 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

  2. 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

    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

  3. HIA Titer for Each of the Three Antigens Contained in the Vaccine at Day 21

    Time frame: 21 days

  4. 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

  5. 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

  6. Percentage of Subjects Demonstrating Seroconversion to Each of the Three Antigens Contained in the Vaccine at Day 21

    Time frame: 21 days

    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.

  7. Frequency and Severity of Occurrence of Any Injection Site Reactions Related to Vaccination

    Time frame: 180 days

    Number of Subjects With Non-Serious Local Reactions During the Entire Follow-Up Period

  8. 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

  9. Frequency and Severity of Occurrence of Any Systemic Reactions Related to Vaccination

    Time frame: 180 days

    Number of Subjects With Non-Serious Systemic Reactions During the Entire Follow-Up Period

Sponsors and collaborators

Lead sponsor

Alachua Government Services, Inc.

Industry

Registry information

Official study 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

Important dates

Study start
2008
Primary completion
2009
Study completion
2009
First posted
Dec 2, 2008
Registry last updated
Nov 24, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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