The War on HPV; A new vaccine that prevents cervical cancer could be available soon.(Cover story)

Byline: Claudia Kalb and Karen Springen

Amelia Togba-Addy, a nurse at Emory Crawford Long Hospital in Atlanta, had always been in good health. But last October her gynecologist called with disturbing news: Togba-Addy's latest Pap smear showed abnormal cells on her cervix. First, doctors removed the suspicious tissue and examined it under a microscope--then they diagnosed Togba-Addy with cervical cancer. In January, she had a hysterectomy. "Even though the doctor says she believes I'm cured and my faith tells me I'm cured, there's still a little part of me that worries," says Togba-Addy, 39. "Before all of this, I didn't even think about cervical cancer."

Few women ever do. Until the Pap smear was introduced in the 1940s, cervical cancer was the No. 1 cancer killer among women. Since then, routine screenings--which detect damaged cells before they become cancerous--have made enormous strides. Over the past 50 years, deaths in the United States have plummeted by more than 70 percent to less than 5,000 a year. But the disease is far from eradicated. Developing countries, where good health care is either inaccessible or unavailable, account for more than 80 percent of deaths from cervical cancer, according to the 2003 World Cancer Report. Every year, half a million women are diagnosed with the cancer and close to 250,000 die.

The disease, however, has a unique and fortuitous characteristic that scientists have exploited in their battle against it: cervical cancer is caused by the human papillomavirus (HPV), a sexually transmitted infection. In June, the U.S. Food and Drug Administration is expected to approve a new vaccine that prevents key strains of HPV; if enough women receive the inoculation, tens of thousands of lives might one day be saved. "This is the first vaccine designed to strike at the root of a cancer," says Dr. Martin Murphy, executive editor of The Oncologist. "Boy, is this a new era."

HPV is one of the most common sexually transmitted infections on the planet--as many as 80 percent of women will be exposed to it at some point in their lives. More often than not, the virus causes no symptoms, is harmless and goes away on its own. Most people don't even know they have it. But certain varieties of HPV (there are about 100 altogether) are particularly aggressive, and two of them--HPV 16 and 18--cause 70 percent of all cervical cancers. Caught early, the disease can be treated with surgery and, if necessary, chemotherapy. But untreated in its advanced stages, it is a painful, gruesome and formidable enemy. In the end, "women bleed to death," says Dr. Diane Harper, of Dartmouth Medical School, and a leading HPV-vaccine investigator.

Under the microscope, HPV looks like a tiny molecular golf ball, with a tough outer shell surrounding a core of infectious viral material. It is a critical ingredient in the shell, a protein called L1, that makes vaccine production possible. Isolated on its own in a petri dish, L1 has acrobatic talent, assembling itself into what scientists call a "viruslike particle" that looks just like HPV, but has "none of the bad stuff inside," says Dr. Eliav Barr, head of the HPV-vaccine program at Merck. Injected into the body, the particles act as decoys, tricking the immune system into recognizing them as HPV. Later, if the real virus hits, the body sees trouble, then assaults and neutralizes the invaders.

Two vaccines, manufactured by Merck and competitor GlaxoSmithKline, have shown remarkable results in clinical trials: close to 100 percent protection against HPV 16 and 18. In rare instances, the strains can cause penile and anal cancer in men; Merck's vaccine also protects against two other types of HPV that cause genital warts in both males and females. Nobody knows exactly how long the vaccines will be effective and when, or if, boosters will be needed. But Merck plans to release five-year data soon and, ...