Increasing the host's defense allows for the body's immune system to fend off attacking pathogens before the person ever knows they have been exposed.

Vaccination programs help the body to create antibodies to targeted pathogens before exposure.

Prophylactic drug use for high-risk patients can help to mitigate the spread of disease by preventing a pathogen from gaining ground over the immune system.

Some interventions attempt to prevent a pathogen from encountering a susceptible host.

Herd immunity  suggests that if a high enough percentage of individuals in a population are resistant to a pathogen, then those few who are susceptible will be protected by the resistant majority.

The theory is that the pathogen will not have a sufficient number of reservoirs available to survive until it finds a susceptible host.