The media has been full of references about herd immunity and its companion individual immunity. The two are inextricably linked, as Ellen Crawford writes. Her article is a good reminder and worth reviewing as it contains horse, human and cattle references.
The three objectives of vaccination are to:
- Induce protection against disease
- Reduce susceptibility of an individual to infection
- Reduce infectivity (shortens time and severity) after the occurrence of an infection
Source: Drover’s, September 22, 2020. Link. The chances of exposure and infection decrease with an increasing number of individuals who are immunized. This results in a decrease in the transmission of the pathogen within the group such that new infections become controlled or extinct.
Also see: How pets protect babies from allergies and obesity, Animal Wellness, April 2017. Link. A study, conducted by researchers at the University of Alberta, showed that when infants are exposed to the dirt and bacteria on their companion animals, it builds their immunity. Interestingly, this exposure begins when the baby is still in utero.