Recently, a new rotavirus vaccine, ROTAVAC®, based on the 116E rotavirus strain and manufactured by Bharat Biotech International Limited of India, demonstrated efficacy in a pivotal clinical trial in India [10] and [11]. Additional rotavirus vaccines are in various stages of preclinical and clinical development. The parameters for the success of such trials from a regulatory perspective will likely differ from the parameters for policy or vaccine introduction decisions, and thus the various study designs used to evaluate efficacy in these trials

are likely to differ. To properly frame the results of clinical trials FG-4592 manufacturer conducted with new vaccines, we reviewed the available literature on efficacy trials of rotavirus vaccines in low-resource settings in Africa and Asia. While acknowledging the importance of safety in regulatory and policy decisions, we limited this review to efficacy outcomes, and to the currently approved and recommended vaccines (Rotarix®, RotaTeq®). Both Rotarix® and RotaTeq® were already approved by

international regulatory authorities www.selleckchem.com/products/PLX-4032.html when tested in Africa and Asia, and thus those trials were conducted primarily to inform policy. Under the assumption that aspects of study design and population characteristics will influence the point estimates of efficacy obtained, we propose that comparisons of point estimates of efficacy from different trials may be challenging, and should be done with a clear understanding of trial design and the variables

that could influence such comparisons. Table 1 provides a number of factors that are known or hypothesized to influence rotavirus vaccine immunogenicity and/or efficacy, with references and examples from clinical trials. We then used these study design characteristics as a framework for evaluating the efficacy data from the new oral rotavirus vaccine, ROTAVAC® as an example of how to interpret appropriately new efficacy results (Table 2). Concomitant administration of oral poliovirus vaccines (OPV) with oral rotavirus vaccines reduces the immunogenicity of rotavirus vaccines, as measured by serum IgA antibody responses and rotavirus vaccine shedding, when compared about with administration of the two vaccines separated in time by 1–2 weeks (Table 1) [12], [13] and [14]. This lower immunogenicity would be expected to result in no effect, or a reduction in efficacy, against clinical outcomes. In moderate to high resource settings, rotavirus vaccines were administered with inactivated poliovirus vaccines (IPV), or separated from OPV administration by at least 2 weeks. In trials performed to date in low resource settings, most of the children received OPV concomitantly with RVs as shown in Table 2. The exception was the trial of RotaTeq® in Africa, where only 35% of children received OPV with RV.