Yesterday, Katie Couric’s daytime talk show weighed in on HPV vaccines. It seems the lack of representation of the benefits of the HPV vaccine was disappointing as many others have pointed out. Read this from Phil Plait for a good breakdown of the segment and corresponding issues. This from Alexandra Sifferlin on the dangers of vaccine misinformation a la Jenny McCarthy. This from Matthew Herper on “Four Ways Katie Couric Stacked the Deck Against Gardasil.” And this from Seth Mookin, really illustrating how disheartening this choice was given literate showrunners.

I have not seen the segment myself but I think more information about HPV, the vaccine and what it can lead to is in order. I’m pleased to introduce Megan Tetlow’s informative guest post on HPV. Megan Tetlow is a Physician Assistant in the subspecialty of gynecologic oncology, providing healthcare to women with cervix, vulvar, vaginal, uterine, and ovarian carcinoma. She is a graduate of the University of North Carolina at Chapel Hill and Nova Southeastern University in Florida.

[Photo credit: http://bit.ly/1d1U1jf]

What is HPV?

HPV (human papilloma virus) is an extremely common virus that is transmitted by sexual contact. In fact, it is the MOST common sexually transmitted infection (1). It has been estimated that 50+% of sexually active adults have had the infection (2), with general medical opinion estimating that today it is probably higher. Rates of infection are highest among young women less than 25 years old (3).

Beyond that, according to the CDC, almost all sexually active adult men and women will be infected with this virus at some point in their lives, even if they’ve had only one sexual partner (1). Additionally, while condoms do prevent other sexually transmitted diseases, they may not prevent transmission of HPV (3).

The lack of knowledge about exactly how widespread this virus is may be one of the barriers to its prevention. Last year I watched an episode of Girls, and the main character’s biggest “baggage” was that she had HPV, when in reality every person on the show probably has HPV and most of the show’s viewers as well. The bottom line is that if you are an adult who is or has been sexually active, it is likely you have or have had HPV, and are potentially at risk for the diseases associated with this virus.

There are over 100 subtypes of the HPV virus. While most of these infections will be cleared by our immune systems, scientists have identified certain sub-types of the virus (specifically subtypes 16 and 18) that are oncogenic, meaning they can give rise to cancer. Oncogenic HPV subtypes are responsible for over 99% of cervix cancers (3). These virus subtypes (16 and 18) have also been found to cause cancers of the mouth, tongue, throat, anus, penis, vulva, and vagina (4). The CDC estimates that vaccination could prevent 22,000 cases of cancer in the US each year (5).

What is the HPV vaccine?

There are two HPV vaccines currently on the market. One is a bivalent HPV vaccine (Cervarix) that works against the oncogenic HPV subtypes 16 and 18.  The other is a quadravalent vaccine (Gardasil) which protects against those two subtypes, as well as sub-types 6 and 11 that are associated with anogenital warts.

Both vaccines are given in a 3 shot series over a 6 month period. Both HPV vaccines are approved and recommended for females ages 9-26. Gardasil has also been approved and is recommended for males ages 9-26. Since HPV is sexually transmitted, the goal age for males and females to be vaccinated is at around 11, with the hopes of being able to administer all 3 vaccinations before an individual becomes sexually active.

Is the HPV vaccine safe and effective?

Both vaccines are licensed, have undergone stringent testing, and have been approved by the Food and Drug Administration for the groups listed above. The CDC and FDA have several systems to continue to monitor safety of a vaccine, including the Vaccine Adverse Event Reporting System (VAERS). VAERS uses patient reporting to track and detect possible new or unexpected adverse reactions to a vaccine (7). Of adverse events reported from 2006 to 2013 through this system, only 7.9% were classified as serious in nature; among these, headache, nausea/vomiting, fatigue, dizziness, syncope (fainting), and weakness were the most frequently reported (8).

While decades of follow-up are certainly required to determine rates of cancer prevention following vaccination, short-term follow-up results have been very promising. The National Health and Nutrition Examination Survey published this year demonstrated a 50% decrease in HPV infections caused by subtypes 6, 11, 16, and 18 in females between the ages of 14 and 19 (9). Countries like Australia that have incorporated the HPV vaccine into the national vaccination program have noticed a significant decrease in genital warts infection among young men and women (10).

What are the barriers to vaccination?

Despite encouraging results, the majority of young men and women are still not being vaccinated.  Based on results of the 2012 National Immunization Survey-Teen, who have been collecting vaccination information on teens with the CDC since 2006, found that only 33.4% of appropriately aged adolescent females had received all 3 doses of the vaccine (8).

Additionally, over 23% of parents surveyed stated they did not plan to vaccinate their child (8). Why are adolescents not getting vaccinated against high risk HPV? In the same study, the most commonly listed reasons against vaccinating were parents felt the vaccine was not needed or not recommended, safety concerns, lack of knowledge about the vaccine and/or diseases it prevents, and that their daughter is not sexually active (8).

As a health care provider, I hear apprehension from parents that vaccinating their child will somehow cause them to be sexually promiscuous or that they are condoning sexual intercourse among adolescents, which is certainly not the case. If an adolescent ever has intercourse over the course of his or her lifetime with just one partner, then he or she is at risk for HPV and HPV-related diseases including cancer.

Overall, these results illustrate how dire education is needed—for patients, parents, friends, and the public. If you are a twenty-something male or female, consider vaccination. If you are a parent who would like to reduce the risk of your child getting cancer but have reservations, tell your healthcare provider and get more information. Only through increased education and awareness can we hope to prevent HPV-related cancers and one day cure science illiteracy.

References

1. Centers for Disease Control and Prevention. Genital HPV Infection—CDC Fact Sheet. Centers for Disease Control and Prevention. 2010.
2. Myers ER, McCrory DC, Nanda K, et al. Mathematical model for the natural history of human papillomavirus infection and cervical carcinogenesis. Am J Epidemiol 2000;151:1158–71.
3. Kevin A. Ault. Epidemiology and Natural History of Human Papillomavirus Infections in the Female Genital Tract. Infect Dis Obstet Gynecol. 2006; 2006: 40470.
4. Cogliano V, Baan R, Straif K, et al. Carcinogenicity of human papillomaviruses.
   Lancet Oncol 2005;6:204.
5. Centers for Disease Control and Prevention. HPV Vaccination- CDC fact sheet. Centers for Disease Control and Prevention. 2013.
6. Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guide- Human Papilloma Virus. Centers for Disease Control and Prevention. 2010.
7. Centers for Disease Control and Prevention. Vaccine safety: HPV Vaccination. Centers for Disease Control and Prevention. 2013.
8. Centers for Disease Control and Prevention. Human Papillomavirus Vaccination Coverage Among Adolescent Girls, 2007–2012, and Postlicensure Vaccine Safety Monitoring, 2006–2013 United States. Centers for Disease Control Morbidity and Mortality Weekly Report. 2013.
9. Markowitz LE, Hariri S, Lin C, et al. Reduction in HPV prevalence among young women following vaccine introduction in the United States, National Health and Nutrition Examination Surveys, 2003–2010. J Infect Dis 2013;208:385–93.
10. Ali H, Donovan B, Wand H, et al. Genital warts in young Australians five years into national human papillomavirus vaccination programme: national surveillance data. BMJ 2013;346:f2032.