This image (http://tinyurl.com/7tt9fw3) is a perfect overview for the clinical trials that must be undertaken when companies are testing drugs/vaccines and healthcare products that are aimed at human use.
This next section, describes the process of clinical trials used in the development of the RTS,S malaria vaccine by GlaxoSmithKline Biologicals, from;(http://www.worldmalariaday.org/download/partners/Updated_RTSS_FactSheet_21_April_2010.pdf)
"Research and preclinical development: Identify relevant antigens and create vaccine concept; preclinical evaluation; develop vaccine manufacturing process.
Phase I clinical trial: Preliminary evaluation of the safety profile and immune response in malaria-naïve and malaria-exposed populations.
Phase II clinical trials: Monitor safety and potential side effects; measure immune response; evaluate efficacy against infection and clinical disease; and determine optimum dosage and schedule.
Phase III clinical trials: Continue to monitor safety and potential side effects, and evaluate efficacy on a large scale.
Submission to regulatory authorities: Submit application to regulatory authorities for approval to market.
Introduction: Make vaccine available for use.
Phase IV clinical trials: Conduct post-marketing safety monitoring; measure duration of protection and assess vaccine compliance".
Efficacy is “the quality of being successful in producing an intended result; effectiveness” (http://www.thefreedictionary.com/efficacy)