WASHINGTON, July 11 (UPI) -- A new vaccine protecting against viruses responsible for cervical cancer, which becomes available this fall for adolescent girls, may face difficulties integrating into existing healthcare, experts said Tuesday.
The vaccine, Gardasil, protects against two types of the sexually transmitted human papillomavirus (HPV): 16 and 18, which together cause 70 percent of cervical-cancer cases. In June the federal Advisory Committee on Immunization Practices recommended the vaccine be given to 11- and 12-year-old girls, before they become sexually active.
"This is a tough population to vaccinate -- it's going to require very unique approaches," said Dr. Thomas Wright, a pathology professor at Columbia University, during a World Cancer Congress symposium.
In general, young adolescents have less access to medical care than children and infants, Wright said. Although vaccination visits are recommended for this age group, many pediatricians do not stress the importance of an adolescent visit.
It's also challenging to immunize adolescents before first sexual activity, which averages 16 in the United States. Studies have shown about 50 percent of girls will become exposed to HPV within three years after onset of sexual activity, allowing a narrow window for vaccination.
In the European Union, school-based health clinics have been overwhelmingly successful in administering the Hepatitis B vaccine to kids, reaching more than 80 percent of students. However, since the ACIP panel did not make Gardasil mandatory to enter school, this approach is unlikely to occur in the United States.
To encourage the vaccine's adoption, pediatricians may not describe the vaccine as an anti-STD vaccine but rather a cancer-prevention measure, Wright said.
Since the vaccine's announcement, much attention has centered around conservative groups worried that an anti-STD vaccine could encourage promiscuous behavior.
But Wright told United Press International people should be careful not to overplay opposition to the vaccine, and parents should be aware it is an effective choice.
The vaccine has shown "spectacular results," and the side effects seem negligible, he added.
"Every mother in America should consider vaccinating her daughter against this," he said.
Gardasil can be administered to women up to 26, as not all those who are sexually active will get HPV immediately. Although the vaccine currently shows no benefit for women who have already had the HPV virus, studies are under way to find out whether the vaccines could prevent future infections.
Twenty million American adults carry an HPV virus at any given time. Most of the infections clear without harm, but a few become cancerous, usually after a 10- to 15-year time lag. About 3,700 women die of cervical cancer yearly in the United States; about 273,000 women die of the disease worldwide, over half of them in the developing world.
Wright also emphasized women should not halt cervical-cancer screening, or Pap smears, once vaccinated. The duration of the vaccine's protection may wane, and it does not protect against 30 percent of cervical cancers not caused by HPV 16 and 18.
Likewise, testing for the presence of HPV alone is unlikely to be useful, Wright said. Much of the technology is not widely available or sensitive enough to detect all HPV infections.
In developing countries, a major focus of the symposium, cervical cancer is the leading cause of cancer death -- mostly because women are not screened through routine Pap smears.
Although childhood immunizations are common and successful in these nations, an HPV vaccine will experience competition from other vaccines perceived to be life-saving, said Dr. Nathalie Broutet of the World Health Organization's Reproductive Health and Research Department.
Overall, an immunization to prevent cancer should be heralded, said Dr. Mark Kane, former director of the Children's Vaccine Program at the Seattle-based Program for Appropriate Technology in Health.
"This is one of the major medical achievements of this century," Kane said. "We ought to be excited to be at the beginning of a discovery of this magnitude."
