Discovering vaccines: the trial tale

This paper reviews the importance of vaccine trials to public health. Vaccines are developed to build immunity to disease, which have helped to completely eliminate smallpox, and reduced incidence of polio and measles. A variety of breakthroughs made many years ago, such as the smallpox vaccine by Edward Jenner and the discoveries by Louis Pasteur, also set the stage for modern international immunization programs. A few events, such as the licensing of the polio vaccine and the passage of the Vaccination Assistance Act helped to improve the study of vaccines. In particular, vaccine trials may be RCTs, cluster trials, or cohort studies. The sample sizes will depend on the objectives, which would include the primary and secondary endpoints. The population under study and the geographical location also affect the trial design. Preclinical evaluation is usually the starting point of vaccine trials, where the safety and efficacy are researched on animal models or cell cultures. Animal models are selected based on their similarity to the target disease. Safety is checked in Phase I, efficacy in Phase II, and both in Phase III. Phase IV is a post-marketing surveillance of the vaccine's safety in real life. Regulatory bodies play a very vital role in ensuring that vaccines adhere to a very high standard of safety and efficacy, such as the FDA, as required. Ethical considerations, such as informed consent and the rights of participants, are innate and are implemented and enforced through laws, regulations, and ethical committees. Vaccine studies vary from the drug studies as it is focused on preventing illness in healthy patients as opposed to cure of diseases in drug trials. The dramatic development in vaccine research was driven by recent pandemics, with parallel processing and data collection in real time. Clinical trials of the vaccine are a foundation stone of public health in the reduction of sickness, offering immunity to diseases, and continuing the fight against infectious diseases. The present review is aimed at describing vaccine trials and their important aspects.