Maintaining Your Health on Mackinac
New Vaccine Recommended To Prevent HPV Infection
By Yvan Silva, M.D.

Human papillomavirus (HPV) is estimated to be the most common sexually transmitted infection in the United States. HPV is transmitted from person to person through sexual contact.

The prevalence of this infection is highest among young people within a few years after initiation of sexual activity. Infection with HPV is not usually associated with symptoms, and many individuals do not know if they were exposed to, or even developed, the infection.

Although the infection is common, it is believed that about 90% of the infections are cleared within two years, when there is no recurring exposure to the virus.

HPV causes genital warts called condylomata accuminata. It also causes some types of oral and pharyngeal warts. More importantly, HPV causes genital cancers in the female - cervical, vulvar, and vaginal - and has been linked to other cancers. In the United States, some 20 million people are believed to have HPV infections; the worldwide estimate is 440 million.

More than 500,000 cases of cancer of the cervix are diagnosed in women every year; the incidence is higher in developed countries.

HPV types of the virus are classified as low-risk and high-risk, according to their association with cancer development. Low-risk types can cause benign or low-grade changes in cells lining the cervix and genital warts; highrisk HPV types can cause cancers of the cervix, anus, and other genital cancers. Highrisk types of the HPV labeled 16 and 18 are detected in 99% of cervical cancers; worldwide, 70% of cervical cancers are owing to high-risk HPV types.

Genital warts are benign and usually cause no problems. They can be treated with prescription medications, or removed with surgical methods.

The well-known Papanicolau (Pap) test remains a very important part of preventive

care - to prevent cervical cancer and detect it in the precancerous phase. Specialized testing can be used in young girls and women to determine if high-risk types of HPV are also present at the time of the Pap test.

If cervical dysplasia is found on a Pap test, that is if precancerous changes in the cells are evident, options include close observation, treatment with cryosurgery, electrocautery removal, or surgical excision.

Treatment of cervical cancer may include removal of the uterus (hysterectomy), radiation therapy, and chemotherapy. Treatment depends on the stage and spread of the cancer at the time of diagnosis.

An innovative breakthrough in the field of preventive health, a prophylactic vaccine against HPV, was approved in June 2006. It is highly efficacious against HPV types 6, 11, 16, and 18. Clinical studies of this quadrivalent vaccine showed close to a 100% efficacy in preventing infection and disease associated with these HPV types.

Recent studies of prevalence of HPV in the United States have shown that the infection rates increased from the ages of 14 through 24 years, and then decreased. Most studies had found the prevalence to be highest in ages below 20 years.

The Centers for Disease Control and Prevention (CDC) recommends routine vaccination with three doses of the quadrivalent vaccine for girls 11 to 12 years of age. Catch-up vaccination is recommended for girls and women ages 13 to 26 years of age, who have not been vaccinated previously or have not completed the full vaccination protocol. Adverse reactions are usually mild and may include pain at the injection site and low-grade fever.

Abstinence, not having any sexual contact at all, is the only sure way to prevent transmission of HPV. Condoms help decrease the incidence of exposure, but do not protect completely against all HPV transmission.

With increasing public awareness of this viral infection, and the widespread implementation of HPV vaccination prophylaxis, a decrease in the prevalence is expected, along with a decrease in infection and cancer rates.

Dr. Silva is a professor of surgery at Wayne State University and a resident of Woodbluff on Mackinac Island.