The New HPV Vaccine: Gardisil 9
Published: Jackson Hole News and Guide, March 2015
Giovannina M. Anthony, M.D.
In 2006, the FDA approved the first HPV (human papillomavirus) vaccine, designed to prevent cervical, vulvar, and oral cancers caused by the most common and virulent HPV subtypes: 16 and 18. The vaccine also prevents infection by HPV subtypes 6 and 11, which cause the common but benign genital wart. Persistent HPV infection leads to cancer of the cervix in 10,000 American women each year. And genital warts? The numbers are in the millions, for both women and men.
Cancers of the anus and head and neck are also possible, and can occur in both sexes. Research on HPV has revealed that subtypes 16 and 18 cause approximately 70% of all of these cancers. In December 2014, the FDA approved Gardisil 9, which adds protection from five additional high-risk subtypes: 31, 33, 45, 52, and 58. This is a 20% increase in the level of protection from the first vaccine and means that Gardisil 9 now protects women from over 90% of the abnormalities caused by the highest risk subtypes.
Sometimes patients will say to me, who cares about HPV vaccination? “I get my pap every year, and pre-cancerous areas on the cervix will be removed before I ever get cancer.” The problem in this country is what I like to call the “burden of HPV disease.” Not a day goes by that I don’t call to counsel a patient about HPV, repeat a pap smear (not exactly fun for the patient), burn off genital warts, scrape the inside of the cervix, biopsy, or excise precancerous abnormalities off of the cervix in a larger procedure. In addition to the stress, anxiety, and discomfort, and multiple time-consuming doctor visits, it costs patients, insurers, and taxpayers billions of dollars each year to manage HPV disease. None of these patients have cancer, but the means of prevention in non-immunized women are invasive and expensive. Why would we not want to prevent the spread of HPV disease?
So what exactly is HPV? It is a virus that is spread by skin-to-skin contact, including sexual intercourse, oral sex, anal sex, and even minimally intimate contact: i.e., hand to genital contact. Condoms do not provide complete protection. Most women and men have become infected with HPV between 15 and 25 years of age. When patients ask me, “why do I have this?” I answer them: everyone has it. HPV disease is what is called endemic: so many of us have it, that it simply lives in the population, spreading with intimate contact. If you are not vaccinated, you cannot avoid HPV.
Fortunately, most people will clear the infection without symptoms and without treatment within two years. However, in 10-20 percent of women, the cervical infection persists and can recur, and both men and women can harbor the virus for years. For this reason regular testing is important in detecting cervical abnormalities early. HPV is classified as either low risk, which causes genital warts, or high risk, which causes cancer.
Because one can pick up HPV without having intercourse, early vaccination is the key to prevention. All of the currently available HPV vaccines are FDA approved to be given as young as age 9, and as old as age 26. The earlier the vaccine is given, the more robust an immune response that results.
I hear some parents say that since their child or children are male, they don’t need to be vaccinated. It is an interesting situation that a parent would vaccinate a boy to protect his future partners, but I believe it is an ethical and appropriate thing to do. If there was a sexually transmitted virus that girls gave to boys that caused a cancer on their genitals, I don’t think there would be any debate in the United States regarding vaccinating those girls. This is an unfortunate consequence of gender relations worldwide. In fact, in many parts of the world, where pap smear screening is unavailable, the HPV vaccine could save thousands of lives.
Another reason to vaccinate both sexes, however, is the fact that HPV causing cancers of the anus and head and neck are on the rise, regardless of sex. The recent death of Farrah Fawcett from an anal cancer caused by high-risk HPV created a lot more media attention regarding this type of cancer. Head and neck cancers are more rare, but they are horrific. Like all HPV-related cancers, these tumors are locally invasive, disfiguring, and devastating. 35% of the anal cancers and over 80% of the head and neck cancers occur in men.
Does the vaccine really work? The original HPV vaccine has been incredibly effective, and there is no reason to think Gardisil 9 will be different. Many studies, some of which involved over 15,000 patients, have been discontinued because the vaccine groups showed such a huge benefit that it was no longer ethical to have a non-vaccinated control group. The protection for both HPV vaccines lasts at least 5 years, but some trials are revealing over ten years of protection, and it may last a lifetime.
A big issue these days is vaccine safety. The most common side effects are mild redness, tenderness, or swelling near the injection site. There is no thimerosal (a mercury derivative used as a preservative) in Gardisil 9, nor in the prior Gardisil product. All medications, including vaccines, have both benefits and risks. In my opinion, the uncommon risks of this vaccine are far outweighed by the benefits of preventing problems that my patients have to deal with every day. For now, however, even women who have received the new vaccine still need pap smears, though in general they are performed less frequently than in years past, now that we know how HPV develops. This new vaccine makes a future where we stop pap smear screening all together a potential reality.
Cancer prevention through vaccination is revolutionary. Availability of these vaccines is something that men and women in the poorest countries of the world can only dream about. Parents should at least consider the option of preventing HPV disease in their children, especially now that the prevention rate is upwards of 90%. Local pediatricians, family medicine providers, and ob/gyns will have more details.