immunogenicity and safety study of an inactivated influenza vaccine (split virus, vero cell derived) in adults aged 50 years and older

Conditions: Influenza

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.