Experts: HPV Vaccine a Preteen Priority
Study Shows Vaccine Is Cost-Effective When 12-Year-Olds Are Vaccinated
HPV Vaccine Strategies continued...
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 prove that.
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 years.
HPV Vaccine: Second Opinion
In an editorial accompanying the study, Charlotte J. Haug, MD, PhD, editor-in-chief of the Journal of theNorwegian Medical Association, has a cautionary note. "The bad news is that the overall effect of the vaccines on cervical cancer remains unknown," she writes.
She points out that although two strains of HPV -- 16 and 18 -- are thought to account for the majority of all cervical cancers and are targets of the HPV vaccine, other strains may emerge as cancer-causing, too.
"We do not know enough about this vaccine yet," she tells WebMD.
In July 2008, the CDC and FDA reported that they had received 7,802 reports of adverse effects in those vaccinated with Gardasil, although the vaccine was not proven responsible for any of those events.
"But it's a very interesting concept and we should definitely go on doing controlled research and see if this is going to work," Haug says. "We are vaccinating young girls, and we are going to see the effect in a couple of decades."
"Vaccine duration is the critical parameter to determine if HPV vaccination is cost-effective," says Diane Harper, MD, professor and director of the Gynecologic Cancer Prevention Research Group at Dartmouth Hitchcock Medical Center and Dartmouth College in Hanover, N.H.
That will take time, she and others acknowledge. Meanwhile, "we have to educate girls and women that the vaccine must be used with the current screening system and is not a substitute for lifetime continued Pap screening," Harper says.