The objective of this Cooperative Center for Translational Research on Human Immunology and Biodefense is to use analysis of vaccine-induced and naturally acquired immunity to influenza A as a model for defining adaptive and innate immune mechanisms and antiviral protection in children and adults. The Clinical Research Core will be responsible for coordinating protocol design and implementation, providing biostatistical support, obtaining human subjects approvals, and creating and managing the centralized database to record clinical and laboratory data. The Clinical Research core will include a laboratory to receive blood and respiratory specimens, carry out initial sample processing and to distribute relevant specimen to the participating laboratories, perform serology assays and analyses. Centralizing these functions^ is particularly important to assure the most efficient use of small volume pediatric blood samples. As the work proceeds, the Core database will facilitate comparative analyses of results obtained from the individual Research Projects. The Specific Aims are Aim 1: To design the clinical study and data analysis plan, make the necessary IRB submissions for clinical studies, recruit and enroll adults and children into clinical protocols, assure that subject rights are respected, and provide follow-up to assure collection of complete sets of data. Aim 2: To provide initial sample processing and distribution of blood or saliva samples to the Principal Investigators, perform standard serologic assays to determine baseline influenza A immune status and measure antibody responses to vaccination or natural infection. The Core will also perform direct influenza A rapid diagnostic tests to recruit children for the study of natural influenza A infection. Respiratory samples for a subset of children in the vaccine study will be collected weekly by Core personnel during the flu season. Aim 3: To provide centralized data management and biostatistical support for the Center. The Clinical Research Support Core will thus administer the clinical protocols under which samples are collected for use in all Research Projects and Research Resource Technical Development Projects.