Traditional vaccines are designed to prevent disease; researchers are working on something new: therapeutic vaccines, vaccinations that treat a disease after you have it. Currently, vaccine research is underway to use therapeutic vaccines to medically treat diseases such as: HIV, Herpes, Alzheimer’s disease and cancer Standard preventative vaccines work by helping your immune system develop immunity to a weakened or dead form of a germ. Then, when you actually come into contact with the live germ, your immune system knows how to fight it off. While the immune system works very well most of the time, some illnesses — like cancer, HIV, and Alzheimer’s — don’t trigger an effective immune response. In the case of some cancers, the immune system simply fails to recognize the invading cells. Other viruses, like HIV, can overwhelm the immune system and shut it down before it can work. Therapeutic vaccines would be used after a person contracts a disease, yet they would still work by boosting your own immune system’s response to an illness. Therapeutic vaccines help by forcing the immune system to recognize a virus or cancerous cell. One specific type of therapeutic vaccines includes: DNA vaccines. One problem with many therapeutic vaccines is that the effects wear off. After a vaccination, the immune system might be aggressive for a while, but eventually return to normal. Some researchers hope they can inject bits of DNA into cells, instructing them to keep the immune system ready to combat the disease.