id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-018677-gmitz3gg	Clemens, John D.	Sequential stages of clinical trials and overview of issues to be considered	2005		.txt	text/plain	6423	270	36	In these studies volunteers are typically allocated at random to receive the vaccine or a comparison agent, usually a placebo, and are then challenged at a defined interval after vaccination with an inoculum of the pathogen predicted to cause the target disease in nearly 100% of the control group. Phase III studies are designed as randomized, controlled trials with clear hypotheses, and are conducted in the target group for whom vaccine licensure is desired and in a population that normally experiences the target infection. Definition of immunological correlates of vaccine protection is very important because such correlates permit assessments of the protection of the tested vaccine and ones suitably similar to it in small, short-term studies with immunological endpoints, without resort to full-scale, Phase III efficacy trials with clinical infection endpoints. The successive phases of clinical evaluation of vaccine candidates allow for acquisition of critical information about vaccine safety, immunogenicity, excretion, transmission, and protection in an incremental fashion, while minimizing the risks to subjects who volunteer to participate in these studies.	./cache/cord-018677-gmitz3gg.txt	./txt/cord-018677-gmitz3gg.txt