During the West African Ebola epidemic between 2014 and 2015, most clinical trials of potential interventions were neither randomized nor adequately controlled, producing results that could not support conclusions about safety or efficacy. This experience should motivate investigators to plan for future public health epidemics so that consensus about trial design and conduct among agencies and local communities can be reached before the next outbreak, according to an article published in Clinical Infectious Disease.

Susan S. Ellenberg, PhD, of the department of biostatistics, epidemiology and informatics, Perelman School of Medicine, University of Pennsylvania in Philadelphia, and colleagues note that randomized controlled clinical trials are essential for obtaining information on the safety and efficacy of vaccines and treatments, even during public health emergencies. Such trials are both ethical and feasible even when dealing with a serious health threat such as the Ebola epidemic.

During the recent outbreak, the numerous organizations providing help to affected areas never reached a consensus on the best way to proceed, resulting in fragmented collaboration, delayed study initiation, and ultimately failure to provide robust data regarding the efficacy of treatments and vaccines.

Some argue that randomization to a placebo control group is unethical during epidemics with a high expected mortality rate.  A “platform” design was proposed during the Ebola epidemic to randomly assign individuals to several different treatments and increase the percentage of participants randomly assigned to treatments that appear to be more effective as the trial progresses. However, the epidemic ended before the trials began.

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The investigators further argue that research and humanitarian organizations must use the inter-epidemic period to improve planning and collaboration so that when another epidemic arises clinical trials of interventions can be initiated quickly.


Ellenberg SS, Keusch GT, Babiker AG, et al. Rigorous clinical trial design in public health emergencies is essential [published online November 21, 2017]. Clin Infect Dis. doi:10.1093/cid/cix1032/4645249