Clinicat Trials of Vaccines and Drugs

Vaccines and drugs are subjected to clinical trials to establish their safety and effectiveness before being licensed for use The design of clinical trials to test vaccines and drugs involve randomised, double blind and placebo controlled protocols

Subjects in a clinical trial are divided into groups in a randomised way to reduce bias in the distribution of characteristics such as age and gender

In a double blind trial neither the subject nor the researchers know which group subjects are in to prevent biased interpretation of the results

One group of subjects receive the vaccine or drug while the second receives a placebo control to ensure valid comparisons