A vaccine trial is a clinical trial that aims at establishing the safety and efficacy of a vaccine prior to it being licensed.
Methodology
A basic vaccine trial might involve forming two groups from a random sample of the target population. One group receives the vaccine while the control group receives a placebo, an adjuvant-containing cocktail, or a different vaccine which might be intended to protect against a different pathogen. Data on antibody production and immunity to the disease in question is collected from both groups some time after the administration of the vaccine or placebo, and a statistical test is performed on these two sets of data to determine whether or not there is any statistically significant difference between them. If the vaccine produces no statistically significant results, then it is rejected. Side effects of the vaccine are also noted, and these too contribute to the decision on whether to license it.
Methodological issues and problems
Vaccine trials may take months or years to complete, since a sufficient time period must elapse for the subjects to react to the vaccine and develop the required antibodies.
