HPV vaccines could save women from cervical cancer

You may have read in recent months that a third or even half of all U.S. women have the deadly sexually transmitted disease HPV, or human papillomavirus. Story after story warns of a massive STD die-off.

The impending death of up to half the female population is used to push abstinence and drum up backing for the recently developed HPV vaccines.

The vaccines are important because they could protect thousands from cervical cancer — the one deadly disease associated with this virus. But most HPV cases never lead to cancer and clear up on their own.

Scientists at the National Cancer Institute say HPV probably does at one time infect at least half the sexually active population. It is more easily transmitted than HIV and more prevalent. You can be chaste and still get infected. A woman can abstain until marriage then get it from her husband.

There's some confusion surrounding HPV partly because it exists in more than 100 different strains. Some HPVs cause "flat" warts on your hands, others "plantar" warts on your feet. About 30 strains can be passed by sexual contact. A few cause genital warts, but contrary to popular belief, these are not associated with cancer. Some strains do nothing.

HPV is so prevalent partly because it's likely to have ridden in human genitalia for hundreds of thousands of years, researchers say.

Strains known as HPV-16, HPV-18 and about 13 others can lead to cancer, but even if you get one of those, odds are that it will clear up by itself.

And if not, Pap smears catch most precancerous growths. These tests do miss some cases though, and women with inadequate health care often don't get screened every year.

And in much of the world there is no cancer screening. That's why 500,000 women get the disease every year — most of them in Africa, the Caribbean and Central and South America and a few other parts of the developing world.

"It's a slow and miserable way to die," says Stephen Rubin, director of Gynecologic Oncology at the University of Pennsylvania. "These tumors grow as ulcerated masses and cause bleeding and infection."

Merck & Co. and GlaxoSmithKline have both developed vaccines that look safe and effective, but they protect against only the two strains that cause 70 percent of cancer cases. The drug companies are now testing the vaccine on men to see if it prevents them from harboring the virus. But scientists still don't understand exactly where or how long the virus hides on the male anatomy.

It's now up to scientists at the Centers for Disease Control to decide how to distribute the vaccine, says Douglas Lowy, a researcher with the National Cancer Institute. "It would be preferable to immunize people before they become sexually active," he says. That could mean giving the vaccine to girls as young as 10 to 12 years old.

"Most people think that you only need this vaccine if you're going to be sexually promiscuous," Lowy says. But the pervasiveness of the virus and the ease with which it spreads suggest the opposite.

The right way to think of the HPV vaccine is to equate it with Pap smears, since it's just another strategy aimed at exactly the same goal — saving lives.

Faye Flam writes for the Philadelphia Inquirer. Her column appears Wednesdays in The Seattle Times.