BY KEVIN AULT, MD
Human papillomaviruses (HPVs) are a group of more than 100 viruses. Some HPV types cause non-cancerous warts on the hands and feet, while other types can be sexually transmitted and cause noncancerous warts on the genitals and the cervix. A few “high-risk” HPV types are the main cause of cervical cancer.
About 6 million new genital HPV infections occur each year in the United States. Most of these don’t have any symptoms and go away without treatment over a few years. Sometimes HPV infection can linger for many years as either a benign or a cancer-causing infection.
According to the National Cancer Institute, more than 11,000 women in the United States (2007) are diagnosed with cervical cancer each year and nearly 4,000 die from it. Rates for cervical cancer in Fulton County are twice the US average. Worldwide, more than half a million women each year develop cervical cancer, which is the most common cause of cancer deaths in women. HPV infection also is a major risk factor for oropharyngeal cancer, which includes the middle part of the throat, the base of the tongue and tonsils. HPV also may contribute to cancers of the anus, vulva, vagina, and penis.
Nearly all sexually active people are going to be exposed to an HPV virus sometime during their lives. Even though for most people, it causes no complications and goes away on its own, about seven percent of the 50 to 60 million pap smears performed in the United States each year are abnormal, and we spend about three billion dollars each year to find and treat pre-cancerous stages caused by some type of HPV.
Although routine pap smears can detect early-stage cervical cancers, the only sure way to prevent HPV infection is to not have genital contact with another person. For sexually active people, a mutually monogamous relationship with an uninfected partner is the best way to prevent HPV infection, but because there aren’t always symptoms, it is hard to know whether someone is infected. Condoms may help protect against HPV infection, but don’t protect completely.
In 2006 the U.S. Food and Drug Administration approved an HPV vaccine named Gardasil (manufactured by Merck) for females 9 to 26 years of age. Emory researchers were part of an three-year international study in more than 24 countries that found the vaccine was 99 percent effective in preventing the two types of HPV responsible for most cases of cervical cancer – strains 16 and 18. The study, which was published in the journal Lancet, also found a high rate of protection from types 6 and 11, which cause about 90 percent of all cases of genital warts.
Gardasil is given in a series of three injections over six months. Another promising vaccine, Cervarix, is produced and is being tested by GlaxoSmithKline, but is not approved yet by the FDA. Both Gardasil and Cervarix also have been tested for safety in thousands of people in the United States and other countries, and thus far, no serious side effects have been found. The most common problem has been brief soreness at the site of injection.
Although some people have questioned giving pre-adolescent girls a vaccine for a sexually transmitted disease, young girls make strong immune responses to this vaccine, which will improve their protection. And it’s better to vaccinate against a disease before it’s needed rather than trying to time it exactly and being too late. Gardasil is proven to be effective only if given before infection with HPVs, along the vaccine may still protect against other HPV types a person hasn’t been exposed to.
The ational Advisory Committee on Immunization Practices (ACIP) has recommended that Gardasil be given routinely to girls ages 11 to 12. The recommendations also allow for vaccination beginning at age 9, and vaccination up to age 26. The ACIP is considering changes to their recommendations that also would include women over age 26 and potentially men.”
Because HPV vaccines do not give complete protection against all HPV types or prevent other sexually transmitted diseases, all women, including those who have been vaccinated, should continue to have regular pap smears to screen for cervical cancer.