Vaccine

Abstract

Humans have tried to fight diseases by the usage of vaccines. Vaccination is a powerful and cost-effective weapon for the prevention of diseases. Because of worldwide vaccination programs, the humans have not only successfully used vaccines to get rid of many childhood diseases but also some of the diseases like smallpox are completely eradicated. Any preparation of virus, bacteria, or their subunits, which is able to impart protection in the individual in which they are administered by activating the immune system, is known as vaccine. As immunization drive starts from childhood therefore it has substantially lowered the morbidity and mortality of children from many infectious diseases.

Vaccination is a mode of active immunization in which attenuated live microorganism or killed microorganism or its specific component is administered in humans. Following exposure to modified pathogenic agent (not able to harm and cause diseases in humans), the immune system is activated. Immune systems’ innate and adaptive branches effectively neutralize the pathogenic agents and its T and B cells owing to their memory response remember their first encounter with the pathogen. Upon subsequent encounter in the due course of time with the same agent, the immune systems’ adaptive branch (T- and B-cell response) effectively and quickly mounts a heightened response and facilitates antigen clearance from the body.

However, despite of tremendous developments in science and technology, some diseases (AIDS, malaria, multiple drug-resistant TB, leishmaniasis) are still big challenges for which we do not have effective vaccines. Vaccines need to be developed for these diseases, which are cause of millions of death worldwide. The chapter is designed to give the insights about the properties of vaccines, adjuvants, attenuated, inactivated, subunit, and nucleic acids as vaccines. This also covers edible vaccines, vaccination for cancer, reverse vaccinology, and generation of vaccines.