What is the difference between a communicable disease and a contagious disease and an infectious disease?

Spread: A communicable disease is a disease many others may get and that is why we have vaccinations. A contagious disease is a disease someone in contact with the person may catch. An infectious disease is a disease that may be spread within the person such as a virus or a bacterial or a fungal infection. An infectious disease may be contagious and communicable but does not have to be.

See below: Communicable and contagious diseases are synonymous and can be spread from a person or environmental source to infect others. Infectious diseases include all diseases caused by microbial agents, some of which are contagious and some of which are not.