Study of Immune Responses After Vaccination Against Seasonal Influenza Virus and Against Influenza H1N1-v Pandemic Virus in a Medical Staff.

Study of Immune Responses After Vaccination Against Seasonal Influenza Virus and Against Influenza H1N1-v Pandemic Virus in a Clinical Staff (FLU-HOP)

This project may help to answer several fundamental questions related to public health regarding vaccination against influenza viruses and regarding the influenza A(H1N1)v pandemy:

What is the immunologic efficacy in terms of antibodies response of the vaccination against the seasonal (2009-2010) influenza virus and against the A(H1N1)v virus in the clinical staff?

Moreover, it may help to answer questions related to the use of a vaccine against influenza virus variants emerging in the French population:

1. Before the vaccination:

   • What is the status of the residual anti-H1N1 seasonal viruses immunity and of the anti-A(H1N1)v immunity in the population stratified by age and taking into account the multiplicity of the prior seasonal vaccinations?
   • What is the level of the cellular and humoral cross-reactivity between the different H1N1 strains?

2. After the vaccination:

   • What is the intensity of the anti-vaccine immune response as a function of the age of the population ad of the prior seasonal vaccinations?
   • What is the level of the cellular and humoral cross-reactivity after vaccination as a function of the age of the population and of the multiplicity of the prior seasonal vaccinations?

Inclusion Criteria:

• Healthy volunteers
• Age superior or equal to 20 years
• Women with childbearing potential using contraception

Exclusion Criteria:

• Documented immune depression
• Current immunosuppressive therapy
• Pregnancy (documented by a positive pregnancy test)
• Breast feeding women
• Documented allergy or hypersensitivity to vaccines
• Documented acute or chronic inflammatory disease
• Concomitant participation to another clinical trial