About vaccination and the third-leading cause of cancer

Published 10:20 pm Saturday, May 16, 2015

Cervical cancer is currently the third-leading cause of cancer death in women worldwide. While the use of Pap smears has been effective at reducing cases of cervical cancer in the United States, still nearly 30 percent of the 11,000 women diagnosed with cervical cancer in this country every year developed it in spite of keeping up with their regular Pap smears. Since the discovery that virtually all cervical cancers are due to infection with the human papilloma virus (HPV), we now have the ability to prevent cancer with a vaccine.
HPV is sexually transmitted but is common, and infected people may not have symptoms right away or may never have symptoms at all. It is estimated that 80 percent of all people will be infected at some point during their lifetime.
The virus consists of many different subtypes. Some of these are classified as “low risk” (associated with the development of genital warts, but not cancers), and “high risk” (associated with development of cancers). Cervical cancer is the most common cancer caused by HPV but it can also cause other genital and anal cancers and may be linked to the development of some oral and laryngeal cancers as well. Since no screening tests like the Pap smear exist for these other cancers, a vaccine that could prevent them would be extremely beneficial. Each year in the U.S. three million women seek treatment of HPV related conditions.
Gardasil, a vaccine directed against the HPV subtypes most likely to cause cervical cancer and genital warts, was released in 2006. The vaccine consists of three separate doses given over six months. It uses manufactured proteins from the virus to trigger the immune system to make protective antibodies. No live or whole dead viral particles are present in the vaccine. Also, the proteins in HPV which cause cancer have been identified, and the vaccine does not contain any of these.
The effectiveness of the vaccine has been confirmed in several studies. In fact, people who have been vaccinated actually have higher levels of protective antibodies in their blood than people who have been naturally infected with the virus itself. In Australia where 80 percent of school age girls receive the vaccination, genital warts cases have decreased 85 percent. If given prior to the onset of sexual intercourse, the vaccine can prevent almost 100 percent of cervical abnormalities that lead to cancer. Once someone is already infected, there is no evidence that the vaccine is still beneficial. For this reason, and because younger teens make more antibodies to the vaccine than older ones do, the U.S. Advisory Committee on Immunization Practices (ACIP) recommends giving the vaccine to girls at 11 to 12 years of age. The American Academy of Pediatrics, American Congress of Obstetricians and Gynecologists, American Cancer Society and World Health Organization all support these recommendations. In addition the ACIP now recommends the vaccine for boys as well, to prevent genital warts and anorectal cancers and to decrease transmission of the virus to unvaccinated girls.
Of course, the recent measles outbreak has spurred renewed debates on the safety of vaccines. Both the FDA and CDC have studied Gardasil and have not noted any increased risks of auto-immune diseases, neurologic disorders or blood clots in those who have received it. Serious events reported following injection with the vaccine are rare and show no particular pattern that would suggest that they are caused by Gardasil, similar to the studies of the tetanus vaccine.
A new version of the vaccine, Gardasil 9, will protect against even more HPV subtypes and will be available in most areas later this year.

Bonnie Corley, MD is an obstetrician/gynecologist with Vidant Women’s Care of Washington located at 1210 Brown Street.