Saturday, August 9, 2008
The Los Angeles Times reports that the safety and effectiveness of the HPV vaccine Gardasil as a preventive cervical cancer treatment for girls are questioned in a report. Linda Marsa writes,
Sandra Levy wants to do everything she can to safeguard the health of her 11-year-old daughter -- and that, of course, includes cancer prevention. She has had her child inoculated with one shot of Gardasil, the human papilloma virus vaccine that may prevent cervical cancer. But now, she says, she has serious reservations about going ahead with the next two injections of the course.
"It's very confusing, and we really don't know if it's 100% safe," says Levy, of Long Beach. "I'm not against vaccines, but I don't want to do anything that would harm my daughter."
Though most medical organizations strongly advocate using the HPV vaccine, some doctors and parents, like Levy, are asking whether the vaccine's benefits really outweigh its costs. They say they aren't convinced that the expensive shots offer any more protection than preventive measures already available -- principally, regular screening via the Pap smear test.
A handful worry that blanket immunizations of the nation's adolescents could backfire by lulling them into a false sense of security that leads them to neglect regular screening. If that happened, vaccination could eventually boost cervical cancer rates instead of lowering them.
In addition, because Gardasil protects only against the HPV strains linked most strongly to cervical cancer, "we don't know if it will make a difference in the ultimate rates of cancer," says Abby Lippman, an epidemiologist at McGill University in Montreal who has researched the HPV vaccine. "The jury is still out on how much benefit we're actually going to get with this vaccine."A report released in June stirred up more doubts. Although cause and effect were not proved, the report listed serious events -- such as seizures, spontaneous abortions and even deaths -- among teens, preteens and young women who had earlier had Gardasil shots.
As a result, the decision -- to vaccinate or not? -- has become controversial. Sorting through the pros and cons can be daunting for many parents.
Promoted on TV
Since its approval in June 2006, Gardasil has been promoted via TV ads featuring girls jumping rope and chanting "One less, one less," a reference to the promise that they won't be another statistic. The vaccine has been hailed by physicians' groups as a breakthrough that could potentially eradicate cervical cancer in the U.S. within a generation.
The American College of Obstetricians and Gynecologists recommended that girls get the required series of three doses (given over a six-month period) at age 9 or older; the American Academy of Pediatrics and the Centers for Disease Control and Prevention recommended the same, with a starting age of 11 or later. (Because HPV is normally spread by intimate contact, the vaccine is considered most effective when given before the beginning of sexual activity. It will not eradicate HPV if someone is already infected.)
Since 2006, about 8 million females in the U.S. have received at least one shot of Gardasil, according to the vaccine's maker, Merck & Co. of Whitehouse Station, N.J., which based these estimates on data from government and private insurers. Of the 100 known strains of HPV, about 30 cause cancer or genital warts. Two -- HPV-16 and HPV-18 -- are responsible for 70% of cervical cancers. Pre-market studies showed that the vaccine is 90% to 100% effective in thwarting the transmission of these two strains and two others, which are linked to 90% of genital warts.
The vaccine is expensive. It costs $360 for the series of three shots, and administrative fees can add $100 or more. Though insurance companies sometimes cover costs, the overall expense for vaccinating the nations' teenagers could run into billions, a bill that will affect taxpayers as the shots are given to recipients of government health programs and health insurance premiums rise.
The price may not be worth it, says Dr. Karen Smith-McCune, an obstetrician and gynecologist at the UC San Francisco School of Medicine. Because it takes years for cervical cancer to develop, it is easily preventable as long as HPV infection is detected early. Though the cancer is common in developing countries and kills more than 280,000 women worldwide every year, it is much less of a health threat in the U.S., she says, where 11,000 women are diagnosed with the disease annually, and about 3,700 will die of it.
The comparatively low U.S. incidence of cervical cancer is due to one of the public health system's triumphs: widespread use of Pap smears, which detect abnormal cervical cells so they can be removed before they turn into cancers. Adoption of the Pap test caused a reduction of cervical cancer rates by 74% between 1955 and 1992, according to the American Cancer Society. Rates continue to drop by 4% each year.
Smith-McCune and other critics of Gardasil also note that up to 90% of HPV infections in adolescents clear up on their own -- meaning that cervical cancer will not develop even in most women infected with the most aggressive type of HPV. In other words, a woman's risk of developing cervical cancer is already extremely low, and the immune system normally makes short work of HPV without outside help.
Even if women get the vaccine, they still need to continue annual Pap screenings because they could contract other cancer-causing HPV strains that the vaccine does not fight.
"The crux of it is that we know how to prevent cervical cancer," Smith-McCune says. "One of the key questions is whether this huge outlay of money for the vaccine is a better strategy than reaching out to the women who aren't getting Pap tests and follow-ups."
It is not yet proven that Gardasil actually prevents cervical cancer, which can take a decade to develop after HPV infection, because tests of the vaccine before the FDA greenlighted it didn't run long enough to prove that conclusively. "Even though it guards against two HPV strains, the other HPV types need to be taken into account," Smith-McCune says. "It will take a long time before we know the true efficacy of the vaccine."
Even doctors who helped devise the vaccine point out that Pap screening may be more effective in cutting cervical cancer rates. "If we vaccinate every single 12-year-old, it should reduce by half the number of cervical cancers in the next 35 years," says Dr. Diane Harper, director of the Gynecologic Cancer Prevention Research Group at Dartmouth Medical School in Hanover, N.H., and a lead researcher in the development of the HPV vaccine. "With Pap screening, we've reduced it by nearly 75%."