Vaccination is the process of receiving a vaccine, which is a substance that stimulates the body's immune system to produce a response to a particular infectious disease. Vaccination is an important tool in preventing the spread of infectious diseases and can help protect both individuals and populations.
Herd immunity is a concept that describes the indirect protection of unvaccinated individuals in a population when a large proportion of other individuals are vaccinated and immune to a particular disease. When a high percentage of a population is immune to a disease, the risk of transmission of the disease is reduced, making it less likely for unvaccinated individuals to come into contact with the disease. Herd immunity only works when the disease is contained to a single host species, and transmission occurs directly from one member of the host species to the other.