The authors thank and acknowledge the contribution of participation of the infants and parents in Taipei, Taoyuan, Taichung (Taiwan),

as well as the investigational staff at National Taiwan University Hospital, Taipei; Chang Gung Children’s Hospital, Taoyuan; Mackey Memorial Hospital, Taipei; Taichung Veterans General Hospital, Taichung; Far Eastern Memorial Hospital, New Taipei City; and at Sanofi Pasteur: Helena Aurell, Isabelle Bruyere, Murielle Carre, Nicolas Corde, Sophia Gailhardou, Christel selleckchem Guillaume, Julia Lin, Agnes Machmer, Celine Monfredo, Zulaika Naimi, Karen Privat, Camille Salamand, Nuchra Sirisuphmitr. This manuscript was prepared with the assistance of a professional medical writer, Alice Walmesley, and funding from Sanofi Pasteur. “
“Most of the serious morbidity and mortality associated with seasonal influenza occur in people 65 and older [1], [2], [3], [4], [5] and [6]. This increasingly large part of the population is a priority for influenza vaccination, but the current vaccine is less effective in

older than younger adults [7] and [8]. In response to the demand for new vaccines that elicit a stronger immune response in older adults, Selisistat various types of influenza trivalent inactivated vaccines (TIVs) are available [9], [10], [11], [12] and [13]. Influenza vaccine effectiveness (VE) is a major consideration in the choice of vaccine, but the relative effectiveness of TIVs in older adults is not well established. Data from direct comparisons of TIVs are needed to inform decisions about which vaccine to use. To be used during the 2011–2012 season, three vaccines were acquired by public tender by the Valencia Autonomous Community (Valencia region) government, and centrally distributed to be offered free of charge to groups targeted for GBA3 influenza vaccination [14]: a split trivalent classical intramuscular vaccine (Gripavac®; Sanofi-Pasteur MSD, Lyon, France); a virosomal trivalent subunit vaccine (Inflexal-V®, Crucell, Leiden, The Netherlands); and a split trivalent intradermal vaccine (Intanza® 15 μg, Sanofi-Pasteur MSD, Lyon, France). The intradermal

TIV seasonal influenza vaccine delivered by a microneedle injection system (Intanza® 15 μg) and the virosomal TIV, intramuscularly delivered influenza vaccine (Inflexal® V) were targeted free of charge to adults ≥65. Enhanced immune response in the elderly is thought to be achieved differently by each vaccine type. Intradermal vaccination provides direct access to the immune system through the dermis, which is rich in immune cells and highly vascularized with an extensive lymphatic network [11] while virosomal vaccination induces high virus-neutralizing antibody titers and primes the cellular arm of the immune system [15]. Health authorities expressed no preference for either vaccine, and both vaccines were widely distributed [14]. Several sources of data can be used to estimate relative TIV effectiveness in Valencia region.