What is HPV and why is it important?


Dr. Thomas deHoop  – Kalispell OB/GYN


“I have teenagers (a son and a daughter) and I keep hearing about the Gardasil vaccine.  Generally speaking I’m not a fan of every vaccine available so is this one mandatory to protect my children?  What are the possible side effects and is it worth the risk?”

Sincerely, A Concerned Mother


This is a good question commonly asked by parents after being offered the vaccine by their pediatrician or gynecologist. Since it’s approval in 2006, Gardisil (and Cervarix in 2009), the human papilloma virus (HPV) vaccine has been administered over 50 million times initially to young women and now men. Despite widespread use, a lot of questions still remain about the vaccine.


What is HPV and why is it important?

The human papilloma virus (HPV) is a common virus that is easily spread by skin-to-skin contact during sexual activity with another person. Less than 5% of people with HPV have symptoms, so it is likely that a person with HPV is unaware making it possible to unknowingly spread the virus to another person. Certain strains of the human papilloma virus (HPV) can cause cancer, of the cervix, vulva, vagina, penis, anus and throat.


Each year in the US, cervical cancer is diagnosed in more than 12,000 women with HPV associated with almost all of them. The human papilloma virus is also believed to be responsible for 2,600 cases of vulvar/vaginal cancer, 4,300 cases of anal cancer and more than 8,400 cases of throat cancer. There are about 120 types of HPV but only about 13 types have been shown to cause cervical cancer with approximately 70% of all cases caused by type 16 and 18. These two types are also responsible for 70% of anal cancers, 70-80% of HPV related penile cancers, 60% of vaginal cancers, and 35% of vulvar cancers. In addition, there are at least 360,000 cases of genital warts each year also caused by HPV.


What vaccines are available?

In the US there are currently two vaccines available: Gardasil and Cervarix. Gardasil was approved for use in 2006 and protects against four strains of HPV. Not only does it protect against type 16 and 18, it also protects against two of the low risk types (6 and 11) that are responsible for up to 90% of genital warts. Cervarix, a lesser-used vaccine, was approved in 2009 and only protects against type 16 and 18. The vaccines offer protection against the previously mentioned cancers as well.


How effective are the vaccines?

Excellent antibody responses have been reported following immunization with both vaccines. In studies where Gardasil was given to women without previous exposure to HPV, it prevented significant precancerous lesions in almost 100% of those who received it. In the overall population study (women with or without prior HPV exposure), the efficacy of Gardasil was approximately 44%. This reduction in efficacy reflects the fact that the majority of the participants were already sexually active and many had been previously infected with the types of HPV the vaccine was designed to prevent. Because the length of time between the infection with HPV and cervical cancer is so long (10 or more years), data on its prevention is still forthcoming. Similarly, clinical trials in men showed an efficacy of over 90% in preventing external genital lesions associated with the HPV types covered by the vaccine. Similar findings were seen with Cervarix.


Who should receive the vaccine and when?

Most of the early studies were on women aged 12-26, which remains the target population. The current recommendation by the US Advisory Committee in Immunization Practices, the American Academy of Pediatrics, the American Academy of Family Practice and the American College of Ob/Gyn is that the vaccine be given at age 11-12 to both boys and girls. For adolescents and young adults who didn’t receive the vaccine at 11-12, they should receive a catch-up vaccination before age 26. Primary reasons for such an early age of administration are; one, the antibody response to the vaccine is as much as three times greater in younger aged females versus those 16 years old and above resulting in greater efficacy. Two, the efficacy is greater when the vaccine given before a person is exposed to HPV. So, receiving the vaccine early, before exposure and with enough time to develop an immune response is the key to the vaccine’s success.


The vaccine is scheduled as a three-shot series over six months. It is given at 0, 1-2 and 6 months. There is no indication that if the series has been disrupted, it needs to be restarted, it just needs to be completed. The vaccine neither treats nor accelerates the clearance of preexisting HPV infections or related disease.


What are the risks with the vaccine?

With over 50 million doses given, it has been found to be as safe as any other childhood vaccine. While common reactions such as soreness or redness at the injection site, nausea and headache do exist, there is no evidence of more serious or dangerous outcomes. Many parents have been concerned that administration of the vaccine may lead to an increase in sexual activity among adolescents. Numerous studies of several thousand children followed into adolescence after being given the vaccine found that HPV vaccination was not associated with an increase in sexual activity or sexual activity related outcomes. It may provide an oportunity to discuss an adolescent’s sexuality.


Who should not get the vaccine?

The vaccines are not currently FDA approved for individuals older than 26, so it shouldn’t be routinely given. There may be some benefit to off-label use that must be decided on a case-by-case basis. Although the vaccines do not contain a live virus, it still should not be used in pregnant women or women who are breastfeeding as it has not been adequately studied in these populations. Studies have shown that those women who inadvertently received the vaccine while pregnant appeared to be at no greater risk of harm to their pregnancy. Lastly, because a woman has been exposed to HPV or has had an HPV related, is not a reason to withhold the vaccine as it is unlikely that someone has been exposed to all of the strains of the virus the vaccine is designed to protect. It will likely benefit those women. Testing for HPV is not a prerequisite to administering the vaccine.


Why should I vaccinate my child?

Like many other vaccines; Hepatitis B, Chicken pox or Whooping Cough, we want to make sure that if exposed at any time in their life, our children are protected. While it is very important to talk to your children about the risks of unsafe sexual practices, at some point in their life they are likely to become sexually active. Even if they only have one lifetime-partner, if that partner has been sexually active in the past, they could harbor the human papilloma virus and potentially expose and transmit the virus. With a vaccine that is nearly 100% successful in preventing transmission of a virus responsible for a majority of anogenital cancers or precancers and genital warts in people who are vaccinated years before becoming sexually active is may be just as important as having “the talk” with your child and offer protection long after they’ve left the nest.


DoctordeHoop072rDr. deHoop is a regular contributor to Health Care Answers in  406 Woman Magazine.

This article  appears in the  April/May 2014 addition online and in print version around the Flathead Valley.

PLEASE NOTE: This information is not intended to be medical advice.  It is general health information and does not take into account your particular health status nor is it a substitute for personal medical care.  Kalispell OB/GYN shall not be liable for any damages arising out of the use of the content herein.