The lack of consistent guidance

on the use of placebo controls raises significant ethical concern. On the one hand, investigators and sponsors may avoid conducting placebo-controlled trials when an efficacious vaccine exists, even if Regorafenib such trials are scientifically necessary and potentially justifiable. On the other hand, a lack of clear guidance may result in the conduct of placebo-controlled trials that are ultimately unethical. Against this backdrop, the WHO Department of Ethics and Social Determinants convened an expert consultation to provide recommendations on the use of placebo controls in vaccine trials in cases where an efficacious vaccine already exists. The focus was on large-scale clinical trials that test vaccines in Phases III and IV of development (i.e. where preliminary testing of safety and immunogenicity, and sometimes efficacy, has been completed in Phase I and II trials). The panel, consisting of 20 experts from Trichostatin A nmr 11 countries, met to discuss relevant issues and develop recommendations in consultation with key stakeholders in international vaccine research (Appendix). The present paper develops the discussion and conclusions from that meeting [13]. Given the high burden of infectious diseases, especially in LMICs, there is an

ethical imperative to develop and test new vaccines. The recommendations from the panel therefore aim to facilitate the conduct of vaccine research

that is ethical, scientifically valid, and designed to meet important public health needs. While this paper focuses specifically on the use of placebo controls, similar considerations apply to open designs in which a placebo is not used, but an unvaccinated control group is included. The following recommendations assume that other common requirements for ethical research are respected [4] and [5]. In particular: Investigators and sponsors consult and collaborate with local stakeholders in all phases of the research; research participants, or their legal representatives, give voluntary and informed consent to study participation; participants are free to withdraw from research at any time, for any reason, without Fossariinae penalty; the research addresses an important health problem and is responsive to local health needs; the study design used minimizes risks and enhances potential clinical benefits for participants; the benefits and burdens of the research are justly distributed; and sponsors, in consultation with national or local authorities, make provisions to ensure reasonable post-trial access to interventions proven most efficacious to the population from which the research participants were drawn. To navigate the difficult ethical terrain of using placebo controls in vaccine trials, it is helpful to identify the conditions under which placebo use is clearly acceptable and clearly unacceptable.