Q+A: Cancer Prevention
August 2, 2019
Kathryn Edwards, MD. Illustration by Sam Kerr.
Kathryn Edwards, MD, the Sarah H. Sell and Cornelius Vanderbilt Professor of Medicine, is one of the nation’s top vaccine experts. A member of the National Academy of Medicine, she focuses on the evaluation of vaccines for the prevention of infectious diseases in adults and children.
Q: Are there any vaccines that can prevent cancer?
A: There are two vaccines that prevent cancer: hepatitis B vaccine and HPV vaccine.
Q: How safe are these vaccines?
A: Both of the vaccines are very safe and highly effective.
Q: What are the recommendations for the hepatitis B vaccine?
A: It is recommended that all children get three doses of hepatitis B vaccine within the first few months of life to protect against liver disease and liver cancer later in life. If the children are born to mothers who are carriers of hepatitis B, then they need to be immunized within the first 12 hours of life and receive hepatitis B antibody to prevent infection. Infants who are infected with hepatitis B at birth have a high likelihood of being chronic carriers and developing liver cirrhosis or liver cancer.
Q: What is HPV?
A: HPV is a very common virus with nearly 80 million people currently infected in the United States. This represents about 20% of the population. Overall, 14 million people, including teens, become infected with HPV each year. Most people with HPV never develop symptoms or health problems. Most HPV infections (nine out of 10) go away by themselves within two years. But, sometimes, HPV infections will last longer and can cause certain cancers and other diseases.
Q: What cancers does the HPV vaccine protect against?
A: HPV infection can cause cancers of the cervix, vagina and vulva in women; cancers of the penis in men; and cancers of the anus and back of the throat, including the base of the tongue and tonsils (oropharynx), in both women and men. Every year in the United States, HPV causes 33,700 cancers in men and women. HPV vaccination can prevent most of the cancers (about 31,200) from ever developing.
Q: When should someone get the HPV vaccine?
A: HPV vaccine is recommended for all older children between 11 and 12 years of age. They should receive two injections of HPV vaccine six to 12 months apart. Adolescents who receive their two shots less than five months apart will require a third dose of HPV vaccine. If the child is older than 14 years, then three shots will need to be given over six months. Also, three doses are still recommended for people with certain immunocompromising conditions, ages 9 through 26. Last year, the U.S. Food and Drug Administration expanded the approved use to include women and men ages 27 through 45 years.
Q: Are there other cancer prevention vaccines being developed?
A: There are a whole series of new cancer vaccines being investigated including vaccines against prostate cancer, breast cancer, lung cancer, colon cancer, pancreatic cancer, renal cell cancer and melanoma. The concept of a cancer vaccine is to produce an immune response against one or more parts of the cancer so that the immune system can fight and destroy the cancer cell. This is similar to a vaccine against an infectious agent like a virus where a vaccine stimulates immunity to the virus so that it can be stopped before it infects the patient or that immunity can be generated to rid the body of the infection. Many of these vaccines are already being studied in clinical trials in people.