Following screening of potential subjects to identify those who are not eligible to participate in plasma donations and to determine the likelihood of having antibodies to influenza A (H1N1 or H3N2) from a recent infection or immunization, enrolled subjects will receive a baseline physical and laboratory examination. Eligible subjects with high influenza A hemagglutination inhibition (HAI) titers will then be scheduled for at least 3 (and up to 20) plasma collection sessions. Following testing of the collected plasma for potential pathogens, it may be used as therapeutic plasma, and/or it may be used for the manufacturing of high titer anti-influenza A intravenous immune globulin (IVIG). Both options would support clinical trials aimed at developing additional therapeutics for influenza infection.