Phase 3
N=3,208
Immunogenicity and Safety Study of an Inactivated Influenza Vaccine (Split Virus, Vero Cell Derived) in Adults Aged 50 Years and Older
Influenza
Bottom Line
View on ClinicalTrials.gov: NCT00782431 ↗Enrolled (actual)
3,208
Serious AEs
4.1%
Results posted
Jan 2026
Primary outcome: Primary: Percentage of Subjects With Seroconversion Antibody Titer — 47.1; 36.8; 63.8; 37.3 percentage of participants
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 3
- Interventions
- Vero cell derived, trivalent, seasonal influenza vaccine (Biological); Licensed egg-derived, trivalent seasonal influenza vaccine (Biological)
- Age
- Adult, Older Adult · 50+ yrs
- Sex
- All
- Sponsor
- Alachua Government Services, Inc.
- Primary completion
- Dec 2008
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Percentage of Subjects With Seroconversion Antibody Titer |
47.1; 36.8; 63.8; 37.3; 68.3; 58.1 | — |
| PRIMARY Percentage of Subjects With Seroprotective Antibody Titer |
29.6; 35.3; 26.7; 36.6; 74.3; 72.6 | — |
| SECONDARY Hemagglutination Inhibition (HI) Antibody Titer for Each of the Three Antigens Contained in the Vaccine at Day 21 After Vaccination |
17.2; 20.3; 15.5; 20.9; 79.5; 67.2 | — |
| SECONDARY Change of Hemagglutination Inhibition (HI) Antibody Titer at Day 21 Compared to Baseline |
4.61; 3.32; 6.87; 3.29; 8.96; 5.65 | — |
| SECONDARY Rate of Subjects Experiencing Any Injection Site Reactions Until the Day 21 Visit After Vaccination |
625; 222; 73; 34 | — |
| SECONDARY Rate of Subjects Experiencing Systemic Reactions Until the Day 21 Visit After Vaccination |
985; 465; 119; 53 | — |
| SECONDARY Rate of Subjects Experiencing Any Systemic Adverse Events During the Entire 180 Day Follow-up Period |
620; 325; 169; 88; 685; 428 | — |
Summary
The purpose of this study is to demonstrate the effectiveness (seroprotection and seroconversion as measured by the hemagglutination inhibition [HI] assay) of an investigational Vero cell-derived, trivalent, seasonal influenza vaccine in adults 50 years of age and older. Subjects will be randomized in a double-blind fashion to receive a single intramuscular injection of either the investigational vaccine or a licensed egg-derived seasonal influenza vaccine. Blood will be drawn from all subjects for a determination of HI antibody titers on Days 0 and 21, body temperature and injection site reactions will be monitored daily for 7 days. In addition, subjects will be monitored for adverse events and rises in body temperature until Day 21 and again until Day 180.
Eligibility Criteria
Inclusion Criteria
- Are 50 years of age or older on the day of screening
- Have an understanding of the study, agree to its provisions, have the ability to adhere to the provisions of the study and give written informed consent prior to study entry
- If female and capable of bearing children,have a negative urine pregnancy test result within 24 hours prior to the vaccination on Study Day 0 and agree to employ adequate birth control measures.
Exclusion Criteria
- History of severe allergic reaction or anaphylaxis to egg protein or any other component of the Vero cell-derived influenza vaccine or the egg-derived influenza vaccine
- Oral temperature of >= 99.5°F (37.5°C) on the day of vaccination in this study (Note: Subjects meeting this exclusion criterion may be rescheduled for vaccination and study entry at a later date if certain requirements [in the study protocol] are met)
- Rash or dermatologic condition or tattoos which may interfere with injection site reaction rating
- Blood transfusion or immunoglobulins received within 90 days of study entry
- Live vaccine received within 4 weeks or inactivated vaccine or subunit vaccine received within 2 weeks of study entry
- Previous vaccination against influenza for the 2008/2009 northern hemisphere influenza season
- Functional or surgical asplenia (e.g. from a history of hemoglobinopathies, leukemias, or lymphomas)
- Diagnosed immunodeficiency as a result of a pathological condition
- Pharmacologically induced immunodeficiency as a result of prescribed administration of corticosteroids (e.g., any systemic administration of corticosteroids or an inhaled dose equivalent to 800 mg of beclomethasone dipropionate) or chemotherapeutics or as a result of radiation therapy or any other modality capable of altering normal immunologic response
- Known or suspected problem with drug or alcohol abuse
- Investigational drug received within 6 weeks prior to study entry or concurrent participating in a clinical study that includes the administration of an investigational product
- Subjects who are 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.
Data sourced from ClinicalTrials.gov (NCT00782431). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.