Immune Activation and Viral Replication after Vaccination with an Influenza A H1N1 2009 Vaccine in HIV-Infected Children Receiving Antiretroviral Therapy

Abstract EN

Immunization with a pandemic influenza A H1N1 2009 was recommended for HIV-infected patients.

However, there is limited information concerning the impact of immunization with this vaccine on immune activation and HIV viral replication.

In this study, 45 HIV-infected children and adolescents receiving antiretroviral therapy were immunized with a 2-dose series of nonadjuvated monovalent influenza A H1N1 2009 vaccine upon enrollment and approximately 1 month later.

Immunogenicity was determined by haemagglutination inhibition assay.

The level of immune activation was determined by identification of CD38 and HLA-DR on CD8+ T cells.

Patients were divided into 2 groups which include patients who had an undetectable HIV viral load (HIV detectable group) and patients who show virological failure (HIV nondetectable group).

The results showed seroconversion rate of 55.2% in HIV nondetectable group, whereas 31.3% was found in HIV detectable group.

Both groups of patients showed no major increase in immune activation after immunization.

Interestingly, a decrease in the frequency of CD8+ T cells that coexpressed CD38 and HLA-DR was observed after immunization in both groups of patients.

We suggested that immunization with influenza A H1N1 2009 vaccine can induce immune response to the pandemic virus without major impact on HIV viral replication and immune activation.