clinical evaluation stage.This is the stage where vaccine candidates begin to be tested on humans. According to the WHO, in phase I clinical studies, initial testing of a vaccine is carried out in small numbers of healthy adults, “to test the properties of a vaccine, tolerability, and, if appropriate,clinical laboratory and pharmacological parameters", primarily to test if it will be safe to administer the vaccine.Phase II trials involve larger numbers of subjects and are intended to test if the vaccine candidate does produce an immune response in subjects, and to once again test for safety.
Phase III involves a large number of participants to fully assess the safety and efficacy of a vaccine candidate. In Indian clinical trials for a.