.Human Papillomavirus, HPV

Overview

Chances are you have been exposed to the human papillomavirus (HPV) and didn't even know it. In fact, it is estimated that at least 75 percent of the reproductive-age population has been infected with one or more types of genital HPV, and up to 6.2 million new infections occur each year. As many as 20 million Americans are estimated to be infected with the genital form of the virus.

The good news: In the vast majority of cases, the virus causes no symptoms or health problems and will go away on its own when a healthy immune system clears the infection. The bad news: A persistent infection with high-risk strains of HPV occurs in about 5 percent of women and causes nearly all cases of cervical cancer, which the American Cancer Society estimates affected an estimated 11,070 women in 2008, killing about 3,870.

In many ways, the issues raised by HPV infection are similar to those raised by genital herpes. Both often have no symptoms; both can cause medical problems in some women; and both have become widespread in this country. Like herpes, persistent HPV is incurable, though some forms of HPV disappear, and it is not yet known whether they completely go away or merely enter a dormant stage, like herpes.

Unlike herpes, however, HPV causes cancer in a small percentage of women and men. In addition to cervical cancer, HPV can also occasionally cause cancers of the vulva, penis, throat and tonsil area and anus.

There are more than 100 types of HPV. The HPV family of viruses is called papillomavirus because they tend to cause warts, or papillomas—benign (noncancerous) tumors. Warts may appear on the hands and feet or on the genital area. The strains of HPV that cause warts to grow on hands and feet, however, are rarely the same type that causes warts in the genital area. More than 30 strains are called genital strains and are spread through sexual contact. Only 15 are associated with cervical cancer; these are called high-risk strains (HPV 16 and 18 cause 70 percent of cancers). Two low-risk strains of HPV—HPV 6 and 11—cause 90 percent of genital warts, though they have no risk of causing cervical cancer.

The U.S. Food and Drug Administration has approved an HPV vaccine, called Gardasil, which can protect women against four HPV types—the two most common high-risk strains (HPV 16 and 18) and the two most common low-risk types (HPV 6 and 11). The vaccine, however, should be given before an infection occurs, ideally, before a girl becomes sexually active. The vaccine is approved for girls as young as nine and is routinely recommended for girls 11 and 12 years of age. It may also be given to women ages 13 to 26 who did not receive it when they were younger, but will not work against the particular HPV type if a woman is already infected with one of the four HPV types in the vaccine. (It will still work against the remaining types she has not yet been exposed to.)

Clinical trials have shown that the vaccine is safe and 100 percent effective in preventing HPV strains 16 and 18. Gardasil, given in three injections over six months, is also 99 percent effective in preventing HPV strains 6 and 11. Although Gardasil prevents two of the most serious high-risk HPV strains in women not previously exposed to them, it doesn't protect against all strains, so the FDA recommends continued screening with regular Pap tests.

The number of invasive cervical cancer cases and deaths in the United States has steadily decreased over the past several decades because of early detection by screening and treatment of cell changes. The cervical cancer death rate declined by 74 percent between 1955 and 1992. Despite the breakthrough of an HPV vaccine, the Pap test remains an important screening test to prevent cervical cancer.

In conjunction with the Pap test, the HPV test, which uses DNA-based Hybrid Capture 2 technology to detect HPV, can be used in women over age 30 to help detect HPV infection. When combined with a Pap test in women of this age group, the HPV test is better at identifying women at risk for developing cervical cancer than the Pap test alone. In addition, two new high-risk HPV tests have been approved by the FDA. One, called Cervista HPV HR, is similar to the DNA-based test and screens for the 15 high-risk strains of the virus; the other, Cervista 16/18, screens for the two HPV types most strongly associated with cervical cancer—HPV 16 and HPV 18.

How is HPV spread?

HPV is spread by skin-to-skin contact with an HPV-infected area. Infections can be subclinical, meaning the virus lives in the skin without causing symptoms. This is why many people with HPV do not know they have it or that they could spread it. For a person exposed to a partner who has a low-risk genital wart-causing strain of HPV such as HPV 6 or 11, it usually takes about six weeks to three months for genital warts to appear. However, infections with high-risk strains of HPV cause no symptoms and can only be detected on Pap or HPV tests.

Researchers already know that condoms don't always protect against the virus because the virus can grow on areas of the genitals not covered by a latex barrier.

Researchers don't know whether people infected with genital HPV but who don't have symptoms are as contagious as people with symptoms. They also don't know how much HPV is transmitted through sexual contact versus skin-to-skin contact.

by :healthywomen.org

Posted in: WOMEN HEALTH