News of the Day ... In Perspective07/06/2006
Condoms, HPV vaccine touted for reducing cervical cancer
A study published in the New England Journal of Medicine showed that consistent condom use reduced the incidence of human papilloma virus (HPV) infection in college women who were newly sexually active. HPV is most the common sexually transmitted disease in the United States.
There was a 70% reduction in the number of women who became infected with HPV if their partners used condoms 100% of the time, compared to those whose partners used condoms less than 5% of the time, after adjustment for number of new partners and number of previous partners of the men.
This reduction was called “pretty awesome” by Dr. Patricia Kloser, an infectious disease specialist at the University of Medicine and Dentistry of New Jersey (AP 6/21/06).
However, the rate of HPV infection in women whose partners always used condoms was still 31.7/100 patient-years at risk, compared to 89.3/100 patient-years at risk if the men used a condom less than 5% of the time.
After 24,201 letters of invitation were mailed, 243 women responded, 210 were enrolled, and 82 were analyzed. The mean duration of follow-up was about 34 months (Winer RL, et al., N Engl J Med 2006:354:2645-2654).
An accompanying Perspective notes that “the protection that condoms offer against a specific sexually transmitted infection cannot be precisely quantified” (Steiner MJ, Cates C Jr., N Engl J Med 2006:354:2042-2043).
On June 29, another means of defense against HPV, the vaccine Gardasil made by Merck, was recommended for use in 11 and 12-year-old girls by the Advisory Committee on Immunization Practices (ACIP). Gardasil is FDA-approved for girls and women aged 9 to 26.
The vaccine protects against four of the more than 100 strains of HPV: strains 16 and 18, which currently account for 70% of cervical cancers, and strains 6 and 11, which cause 90% of the cases of genital warts. Three doses are given over 6 months, at $120 per dose, making it one of the most expensive vaccines on the market. ACIP approval makes it likely that insurers will cover it.
According to the American Cancer Society, about 9,710 new cases of invasive cervical cancer are expected to be diagnosed in the United States this year, and about 3,700 women are expected to die from the disease (Jennifer Corbett Dooren, Wall St J 6/29/06).
The cost-effectiveness of the vaccine is controversial. Various studies calculate a cost of $14,000 to $60,000 per quality-adjusted year of life saved. It is assumed that Pap smears would be used every 2 to 3 years, and that a booster shot would be given in 5 to 10 years. The vaccine has been shown to be effective for at least 5 years (Shirley Wang, Wall St J 6/29/06).
The next steps are likely to be automatic school mandates, massive federal spending for the vaccine, higher insurance premiums for all, sweeping liability protections for the manufacturer, and harassment of families who don’t want their child to receive this vaccine, writes Dawn Richardson, president of PROVE (Parents Requesting Open Vaccine Education).
The National Vaccine Information Center states that safety testing of the vaccine is inadequate.
“Merck’s pre and post-licensing marketing strategy has positioned mass use of this vaccine by pre-teens as a morality play in order to avoid talking about the flawed science they used to get it licensed,” states NVIC president Barbara Loe Fisher. “This is not just about teenagers having sex, it is also about whether Gardasil has been proven safe and effective for little girls.”
The safety trials utilized a potentially reactive aluminum adjuvant instead of a nonreactive placebo control. About 60% of recipients of both Gardasil and the control preparation had adverse systemic reactions. Arthritic symptoms occurred in 9 of 11,813 Gardasil recipients and 3 of 9,701 controls. Most of the 102 serious adverse reactions in study participants, including 17 deaths, were dismissed as unrelated. The number of girls under age 16 in the trial was not revealed (NVIC press release, with references, 6/27/06).