Vaccines are biological pharmaceutical products prescribed as prevention of a hypothetical infection. Development of a new vaccine is the result of a long process involving several stages. During all developmental phases, priority is the safety of the new product, which is often used in young infants. The initial research phase lasts 1-5 years and is followed by a clinical and pharmaceutical development phase (preclinical and clinical phases), which can last from 15 to 20 years on average before licensure is obtained. There are, however, exceptions, like the malaria vaccine for which research has been going on for more than 30 years and at least 30 candidate vaccines have been assessed. This chapter summarizes the different phases of vaccine candidate development from preclinical studies to phase 2 vaccine trials.
Keywords: Challenge; Clinical trial; Safety; Vaccine development.