A heterologous vaccine (also known as a "Jennerian" vaccine) is a type of live vaccine where one pathogen is introduced in order to provide protection against a different one. The vaccines are pathogens of other animals that either do not cause disease or cause mild disease in the organism being treated.
Examples include:
Like all live vaccines, it has the advantage that it replicates in the body, and therefore reduces the need for booster shots. It has the disadvantage that a potential pathogen is introduced into the body.
It can be combined with the attenuation strategy in vaccine design.
References
Heterologous vaccine Wikipedia(Text) CC BY-SA