Experts: HPV Vaccine a Preteen Priority
Study Shows Vaccine Is Cost-Effective When 12-Year-Olds Are Vaccinated
Aug. 20, 2008 -- The vaccine against human papillomavirus (HPV), the sexually transmitted virus that causes cervical
cancer, will be most cost-effective in the U.S. with universal vaccination
of 12-year-old girls and catch-up efforts to vaccinate girls and women ages 13
to 21, say Harvard researchers.
"We really should be targeting and prioritizing the younger girls,
12-year-olds, prior to sexual activity," says Jane J. Kim, PhD, assistant
professor of health decision science at the Harvard School of Public Health and
lead author of the study.
That, coupled with a temporary catch-up program to vaccinate girls and women
ages 13 to 21, could make it possible to revise current cervical cancer screening so that women
could begin screening somewhat later and undergo it a bit less frequently, she
But an editorial in the New England Journal of Medicine, raises
questions about the effectiveness of the vaccine in preventing cervical
The study, also published in the New England Journal of Medicine, is
one of many investigations undertaken by Kim and her colleagues over the years
on prevention of cervical cancer, which struck more than 11,000 women in the
U.S. in 2007 and killed 3,600.
Her report is meant to evaluate cost-effectiveness and guide public health
"We used mathematical models to simulate the natural history of the
disease," Kim says, "then superimposed these strategies, whether they
be screening, HPV
vaccine, or a combination of both."
After FDA approved the HPV vaccine Gardasil in 2006, the CDC recommended
routine vaccination of girls ages 11-12 and catch-up vaccination of girls and
women ages 13 to 26.
HPV Vaccine Strategies
Kim pooled data to predict both the health and economic outcomes of HPV
vaccination of girls age 12, with catch-up vaccinations over a five-year period
of girls 13 to 21 coupled with routine cervical cancer screening.
She plugged in various strategies to include catch-up programs to ages 18,
21, or 26. The main focus was to see how well each strategy prevented cervical
To determine the cost-effectiveness, Kim took into account the benefit of an
intervention such as a vaccine in terms of the person's health and also the
cost of the intervention. Experts agree that costs and health benefits at a
specific threshold are a good value, while those above the threshold are not a
good value, at least from a public health perspective.
Kim's team plugged in an assumption that the vaccine effectiveness was going
to be lifelong -- which is still an unknown because the vaccine is too new to
The cost-effectiveness for routine vaccination of 12-year-old girls,
assuming they underwent screening as now recommended, was a good value.
To a point, the catch-up program was a good value, too. "We found the
vaccine up to the age of 18 was consistently favorable," Kim says. "Up
to age 21 was favorable under generous assumptions about its efficacy. Up to
age 26 was consistently unattractive in terms of cost-effectiveness."
Kim concludes that if most 12-year-old girls get the vaccine, their cervical
cancer screenings -- such as Pap tests and HPV
tests -- could begin somewhat later than what is recommended by the CDC,
starting within three years of first intercourse and no later than age 21. And
the screenings could be done a bit less frequently, such as every three to five