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The HPV Vaccination

By Tiffany Spudich, R.Ph., Pharm. D.

Genital HPV infection is a sexually transmitted disease (STD) that is caused by human papillomavirus (HPV). The Centers for Disease Control and Prevention (CDC) estimates that 20 million people are currently infected with HPV. At least 50 percent of sexually active men and women acquire genital HPV infection at some point in their lives. By age 50, at least 80 percent of women will have acquired genital HPV infection. About 6.2 million Americans get a new genital HPV infection each year.

Human papillomavirus is the name of a group of viruses that includes more than 100 different strains or types. More than 30 of these viruses are sexually transmitted, and they can infect the genital area of men and women including the skin of the penis, vulva (area outside the vagina), or anus, and the linings of the vagina, cervix, or rectum

Some of these viruses are called "high-risk" types and may cause abnormal Pap tests. Very rarely, HPV infection results in anal or genital cancers. Others are called "low-risk" types, and they may cause mild Pap test abnormalities or genital warts. Genital warts are single or multiple growths or bumps that appear in the genital area, and sometimes are cauliflower shaped. The types of HPV that infect the genital area are spread primarily through genital contact.

Most women are diagnosed with HPV on the basis of abnormal Pap tests. A Pap test is the primary cancer-screening tool for cervical cancer or pre-cancerous changes in the cervix, many of which are related to HPV. Also, a specific test is available to detect HPV DNA in women. The test may be used in women with mild Pap test abnormalities, or in women >30 years of age at the time of Pap testing. The results of HPV DNA testing can help health care providers decide if further tests or treatment are necessary. Currently, there is no test designed to find HPV in men. But HPV is very common and most men with HPV will never develop health problems from it. Finding out if you have HPV is not as important as finding out if you have the diseases that it can cause. Every year in the U.S. about 10,000 women get cervical cancer and 3,700 die from it. It is the 2nd leading cause of cancer deaths among women around the world.

After sexual contact with an infected person, warts may appear within weeks or months, or not at all. Visible genital warts can be removed by medications the patient applies, or by treatments performed by a health care provider. Some individuals choose to forego treatment to see if the warts will disappear on their own. No one or specific treatment regimen for genital warts is better than another, and no one treatment regimen is ideal for all cases. Most people who become infected with HPV will not have any symptoms and will clear the infection on their own. There is no "cure" for HPV infection, although in most women the infection goes away on its own.

The treatments provided are directed to the changes in the skin or mucous membrane caused by HPV infection, such as warts and pre-cancerous changes in the cervix. If the immune system is not able to clear the infection and the virus lingers, HPV can cause genetic changes in cells in the cervix, affecting their ability to control normal growth. When looking at all kinds of cancer, this sort of trigger is unusual: viral infections are not considered a common cause. But there are other examples of cancer-causing viruses, including hepatitis C, which can result in liver cancer.

HPV infection can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered. While the effect of condoms in preventing HPV infection is unknown, condom use has been associated with a lower rate of cervical cancer, an HPV-associated disease. The surest way to eliminate risk for genital HPV infection is to refrain from any genital contact with another person. However Gardasil®, another option to help prevent HPV infection, was just approved by the FDA on June 8th, 2007. Gardasil® is an inactivated (not live) vaccine which protects against 4 major types of HPV. These include 2 types that cause about 70 percent of cervical cancer and 2 types that cause about 90 percent of genital warts. The HPV vaccine can prevent most genital warts and most cases of cervical cancer.

Protection with the HPV vaccine is expected to be long-lasting. But vaccinated women still need cervical cancer screening since the vaccine does not protect against all HPV types that cause cervical cancer. Gardasil® is routinely recommended for girls 11 and 12 years of age, but doctors may give it to girls as young as 9 years. It is important for girls to get the vaccination before their first sexual contact – because they have not been exposed to HPV. For these girls, the vaccine can prevent almost 100 percent of disease caused by the 4 types of HPV targeted by the vaccine. Gardasil® is also recommended for girls and women 13 through 26 years of age who did not receive it when they were younger. If a girl or woman is already infected with a type of HPV, the vaccine will not prevent disease from that type. There is no data suggesting that the vaccination would be effective in females over the age of 26 and as such, insurance policies would probably not cover it in this case.

It is likely that the FDA will consider approving the vaccine for men. Even though men do not develop HPV-related cancers, they do spread the virus to women. Also, a recent U.S. study suggested that, in addition to girls and young women, men and boys should be given the HPV vaccine. That finding comes from a Brown University study that determined alcohol and tobacco use do not increase the risk of head and neck cancers for people with the HPV type 16. HPV16 is a common strain of the sexually transmitted HPV virus, another known risk factor for head and neck cancer. Researchers said their finding is the strongest evidence to date that such cancers have two distinct causes and might represent two distinct classes of cancer.

Study leader Dr. Karl Kelsey said the research has public health policy implications, since the HPV vaccine is restricted to females to prevent cervical cancer. However, up to 75 percent of sexually active U.S. men and women are infected with HPV at some point in their lives. Our current HPV vaccine recommendations should change, Kelsey said. Head and neck cancers, regardless of their cause, are predominantly male diseases. If boys and men received the HPV vaccine, a lot of these cancers could be prevented.
Merck, Gardasil’s® manufacturer, has ongoing trials looking at the effects of Gardasil® for protecting men from HPV.

The vaccination is administered as 3 separate dosages: the first dose at elected date, the second dose 2 months after the first dose, and the third dose 6 months after the first dose. Additional booster doses are not recommended. Anyone who has ever had a life-threatening allergic reaction to yeast and pregnant women should not get the vaccine. People who are mildly ill when the shot is scheduled can still get the HPV vaccine, but those with moderate to severe illness should wait until they recover.

Gardasil® does not appear to cause any serious side effects, although injection site reactions have been reported including pain and redness at injection site, swelling and itching at injection site, and fever. The HPV vaccine is not recommended for every woman, so as with any important health issue, you should discuss the new vaccine with your doctor.

1. www.cdc.gov
   
2. www.prevention.com
   
3. http://online.factsandcomparisons.com
   J Natl Cancer Inst. 2007 Dec 5;99(23):1801-10. Epub 2007 Nov 27.
   
   
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