H9 Priming Study in Healthy Adults
Condition: Influenza
MeSH terms: Influenza, Human
Study type: Interventional
Phase: Phase 2

Summary: 
      The purpose of this research study is to determine whether prior exposure to A/H2N2 viruses
      is associated with better antibody (part of the immune system that fights infection)
      responses after vaccination with an A/H9N2 flu vaccine. The study will evaluate how much
      antibody is made to the influenza virus after H9N2 flu vaccination and how the body reacts to
      different strengths of the H9N2 flu vaccine. This information may guide vaccine development
      for this virus as well as other bird flu viruses that have infected humans. Study
      participants will include 120 healthy subjects, age 18-38 or 44-59 years. Two different
      dosages of vaccine will be given in the muscle of the upper arm about 1 month apart. The
      assignment of vaccines to participants is governed by chance. Study procedures may include
      medical history, physical exam, and blood samples. Study participation duration is about 7
      months.
    

Detailed description: 
      Influenza A viruses have the potential to cause worldwide epidemics and/or pandemics
      resulting in significant morbidity and mortality. The goals of this study are to determine
      whether persons over 44 years of age (born before 1964) have evidence of priming to influenza
      A/H9N2 viruses as measured by responses to two different dosage levels of an A/H9N2 vaccine.
      Evidence of priming for persons born before 1964 has implications in pandemic preparedness
      planning in that such individuals may need only a single vaccination to induce immunity
      compared to persons who are not immunologically primed. This study will also explore the
      immunogenicity of two-dose regimen using a homologous A/H9N2 virus as an antigen for the
      hemagglutination inhibition assay (HAI) and neutralizing antibody assays. Approximately 120
      healthy adults will be enrolled into this single-center, randomized, double-blind trial of
      subvirion inactivated influenza A/H9N2 (G9 variant) vaccine given by intramuscular (IM)
      injection. Subjects will be stratified by age, with 50 percent in each dosage group being
      between the ages of 18 and 38 inclusive and the other 50 percent being between the ages of 44
      and 59 years, inclusive. Subjects will be randomized 1:1 to receive 2 doses one month apart
      of one of two dosages (7.5 micrograms or 30 micrograms) of A/chicken/Hong Kong/G9/97
      subvirion vaccine. The subjects and staff responsible for assessing responses after
      vaccination will be blinded to the dosage level that is administered. All subjects will
      receive two doses of their assigned dosage level given by the IM route separated by
      approximately 28 days. Subjects will be observed in the clinic for approximately 20 minutes
      after vaccination. Subjects will maintain a memory aid recording oral temperature, and
      systemic and local adverse events for 7 days after each inoculation. They will return to
      clinic on day 8 after vaccination (window 8-10) for adverse event (AE) assessment,
      concomitant medication assessment, a targeted physical exam (if indicated), and review of
      memory aid. AE data will be captured Day 0 through Day 56. Serious adverse event (SAE) data
      will be captured from Day 0 through the end of the trial (7 months after the first dose of
      vaccine). Serum for immunogenicity evaluations will be obtained prior to the first
      vaccination, at Day 0, prior to the second vaccination, at Day 28 and at Day 56. The primary
      objective is to determine whether persons 44-59 years of age show evidence of immunologic
      priming to A/H9 virus compared to persons 18-38 years of age. The secondary objectives are to
      evaluate dose-related immunogenicity 4 weeks after each vaccination and to evaluate the
      safety and tolerability of the vaccine.
    

Intervention name(s): Subvirion inactivated influenza A/H9N2 (G9 variant) vaccine
Intervention type(s): Biological
Intervention description(s): Inactivated subvirion influenza A/chicken/Hong Kong/G9/97 (H9N2) vaccine administered via intramuscular (IM) injection, dose 7.5 or 30 micrograms.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: vaccine, priming, influenza, flu, A/H9N2