As women—and soon men—gain access to the new Merck vaccine Gardasil, which targets the sexually transmitted human papillomavirus, the Centers for Disease Control and Prevention has stepped up efforts to identify the 25,000 or more cancers primarily associated with HPV that increase the burden of cancer in the United States each year. As reported in the November 15 supplement to the journal Cancer, the latest figures include 10,846 patients with invasive cancer of the cervix, followed by 7,360 with cancers of the mouth, particularly the tonsils and the back of the tongue. In addition, there are 3,018 cancers of the anus, 2,266 of the vulva, and 828 of the penis.
To the CDC, these are baseline numbers to track the life-threatening consequences of HPV infection. To sexually active young people, this report should be a wake-up call. The hows and whys of catching contagious warts and cancer through sex should be part of every parent's birds-and-bees talk, every school's sex-ed curriculum, and—most of all—all young people's thinking about their own sexual vulnerability. Here are seven need-to-know facts:
- Infected boys and men are silent carriers of HPV, spewing out their contagion in body fluids. With some strains, visible warts on the genitals bud off fresh virus.
- Infected girls and young women (particularly vulnerable to infection because of a still-developing cervix) also shed abnormal cells bearing virus into Pap smears, tests that sexually active women should have yearly. The atypical cells usually clear in anywhere from a few months to two years.
- For well over 50,000 young women each year, the infection hangs on and progresses to a very early in situ cancer of the cervix. If detected before it invades local tissue, it can be cured with a minor surgical procedure. If not, a woman's fertility and life are threatened.
- There is no screening test akin to the Pap smear for other HPV infections. Accordingly, the noncervical HPV-linked cancers are detected at more advanced stages, often requiring extensive and disfiguring treatment.
- Risk factors for HPV include having multiple sexual partners, being under 26 years of age, and practicing oral or genital sex without a condom. Infection risk also increases with smoking, use of birth control pills, and coinfection with other STDs like chlamydia.
- Except for one's own strong immune system, there is no medicine to treat an HPV infection.
- Preventive immunization is a huge advance but not a sure bet. Gardasil targets the four most dangerous strains (HPV 16, 18, 6, and 11), not all. It's estimated that 30 percent of HPV-related cancers and 10 percent of warts can still slip through.
A universal caution echoed by some of my readers: Even the best vaccine can have side effects and does not eliminate the need for healthful habits and prudent behavior.