Your immune system protects you from illness and foreign substances that can harm you.
Scientists have found a way to use the body's immune system to help treat or prevent many health problems. This treatment is known as immunotherapy.
Immunotherapy may be used to:
Prevent illnesses. Routine vaccines are a type of immunotherapy. Vaccines get your immune system to learn to respond to a possible infection. Then your immune system will fight it off quickly if it ever sees it in the future. Vaccines are made of tiny amounts of weakened or dead viruses and bacteria. So they shouldn't make you sick.
Prevent cancer. Cancer vaccines help protect against viruses that can cause some cancers. One example is the vaccine for human papillomavirus (HPV). This virus causes cervical cancer, as well as other cancers.
Control asthma and allergy symptoms. Immunotherapy shots are often given if you have severe allergies or asthma. The shots start with a small amount of allergen. This helps your immune system build up a tolerance to that allergen. You are then less sensitive to the allergen and have fewer symptoms.
Treat or manage cancer. Immunotherapy may be used with other treatments to help them work better. It works best to treat early-stage cancers.