A vaccine stimulates the immune system to produce antibodies to fight a disease.
Most vaccines help protect us from infections, such as measles or polio. They are made from weakened or killed germs that do not cause the infection but cause the immune system to make antibodies against the germs. You will then be protected from getting the infection if you come in contact with it.
Cancer treatment vaccines are different because they try to get the immune system to attack cancer cells that are already in the body. Most cancer treatment vaccines are still being studied in clinical trials.
Vaccines to prevent cancer
Preventive (prophylactic) vaccines are used to prevent viral infections that cause cancer or contribute to cancer development. They are designed to stimulate the immune system to attack certain viruses before they cause an infection. These vaccines are given to healthy people before cancer develops.
Human papillomavirus (HPV) vaccines protect against infection caused by certain types of HPV. The 3 HPV vaccines available in Canada are Gardasil, Cervarix and Gardasil 9. These vaccines help protect against infection with types of HPV most commonly linked with precancerous conditions and cervical cancer. Gardasil 9 also protects against other types of HPV that can cause cancer.
Currently, HPV vaccines are approved in Canada to prevent cervical cancer related to HPV. This virus is also associated with vaginal, vulvar, anal, penile and some oral cavity and throat (pharyngeal) cancers.
Hepatitis B vaccines may lower the risk of developing liver cancer in some people. Hepatitis is inflammation of the liver that can be caused by certain viruses. People with long-term infection with the hepatitis B virus (HBV) are at a higher risk of liver cancer.
Vaccines to treat cancer
Cancer treatment vaccines can be made up of cancer cells, parts of cancer cells or antigens. These vaccines are made to recognize proteins on certain cancer cells. This helps the immune system to recognize and attack those cancer cells. These vaccines might eventually help to stop further growth of the cancer, prevent a cancer from coming back and destroy cancer cells left behind after other treatments.
The following cancer treatment vaccines are most commonly studied.
Whole tumour vaccines use the whole cancer cell, not just an antigen, to make the vaccine. The vaccine is made from your own cancer cells, cancer cells from another person or cancer cells grown in a lab.
Antigen vaccines are made from antigens in cancer cells. The goal is to stimulate the immune system to attack the cancer.
Dendritic cell vaccines are made from dendritic cells that are grown in a lab together with cancer cells. The vaccine should stimulate your immune system to attack the cancer.
DNA vaccines are made with bits of DNA from cancer cells. The vaccine should make the cells of the immune system better at reacting to and destroying cancer cells.
Anti-idiotype vaccines stimulate the body to produce antibodies against cancer cells almost in the same way as antigen vaccines. An idiotype is the part of an antibody that determines the specific antigen the antibody will act against.
Side effects of cancer vaccines
Side effects can happen with any type of treatment, but everyone’s experience is different. Some people have many side effects. Other people have few or none at all.
Side effects of cancer vaccines will depend mainly on the type of vaccine and usually last for only a short time. Tell your healthcare team if you have these side effects or others you think might be from cancer vaccines. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.
The most common side effects that people tend to experience with cancer vaccines are:
A type of protein made by the immune system that disarms or destroys a specific foreign substance (antigen) when it appears in the body.
A foreign substance that stimulates the immune system to produce antibodies against it.
A type of white blood cell that helps fight infection by producing signals (antigens) to boost the immune response (the immune system’s reaction to the presence of foreign substances in the body).
Dendritic cells develop from monocytes (a type of white blood cell that helps fight infection by eating bacteria or other foreign substances) that have moved from the blood into tissues.