Surveillance of Influenza Virus Shedding and Immunologic Response in Immunocompromised Children and Young Adults

This study aims to do the following;

• To evaluate the frequency of influenza virus infections due to various subtypes in immunocompromised children and young adults at SJCRH
• To describe and compare the clinical course and outcome of pandemic H1N1 influenza infection with that due to other influenza virus subtypes in immunocompromised children and young adults.
• To evaluate the duration of influenza virus shedding in immunocompromised children and young adults.
• To evaluate the immunologic response to natural infection with various subtypes of influenza virus including the pandemic H1N1 influenza A virus.
• To evaluate the viral resistance to antiviral agents in relation to antiviral therapy.
• To compare accuracy of rapid methods for influenza A subtyping and for determination of antiviral resistance.

Inclusion criteria

• Age <= 21 years of age at the time of entry into the study.
• Body weight of 13 kg or greater
• An immunosuppressed state due to cancer, sickle cell disease, HIV, or receipt of stem cell transplant
• Presentation with acute respiratory illness defined as recent onset of rhinorrhea, nasal and sinus congestion, pharyngitis, coryza, sinusitis, otitis media, dyspnea or shortness of breath, cough and/or a new radiographic pulmonary infiltrates.
• Proven influenza virus infection by virological testing of respiratory specimens using Polymerase Chain reaction (PCR) assay, direct antigen detection assay, or viral culture.

Exclusion criteria

• Inability or unwillingness of research participant or legal guardian to give written informed consent.