Preventive vaccines: these are the typical vaccines against infections, such as those applied in childhood. Their purpose is to protect against eventual infections which can be caused by the pathogens targeted by the vaccine. The enhanced immunity generated after vaccination persists for long periods of time in the absence of changes in the infectious agents. However, they sometimes change their structure (mutations) which requires successive vaccinations to ensure efficient protection. This is the case of the fever vaccine.
Therapeutic vaccines: this type of vaccine is designed for treating patients for a disease which is sensitive to the effect of the vaccine. These vaccines induce an immune response which cannot be obtained otherwise. In these cases, vaccination can have a positive effect on the type of response normally given by patients and which could be counter-productive for them (for instance, an allergic response).
