The Fast Track

Should governments and school systems require girls and young women to get the human papillomavirus (HPV) vaccine, which helps prevent cervical cancer? A new study in the Aug. 21 edition of the New England Journal of Medicine (NEJM), examining the cost-effectiveness of the vaccine for 12-year-old girls versus young women, is adding fuel to the debate.

Pharmaceutical company Merck got FDA approval in June 2006 to market the vaccine, Gardasil, to females ages 9 to 26. Millions of girls have been vaccinated since then, but not without controversy over the idea of immunizing young girls against a virus that is sexually transmitted. (The vaccine protects against the two types of HPV that cause 70 percent of cervical cancer worldwide, and against forms of the virus that cause 90 percent of genital warts in both men and women.) Another point of contention has been the vaccine's cost--about $360 for three shots taken over six months. This week's NEJM report indicates that the vaccine appeared to be cost-effective for 12-year-olds, assuming that immunity doesn't wane after 10 years; in that case, a booster shot would be required. It also found that "catch-up" programs for 20-somethings may be too expensive.

An NEJM editorial accompanying the study raises other questions about whether the vaccine provides lifelong protection from the virus and whether it should be required by public health officials. "This is still an experiment. And it should be treated that way," says Charlotte Haug, editor in chief of the Journal of the Norwegian Medical Association and author of the NEJM editorial. "There are good reasons to take a deep breath and keep doing the research."

Karen Springen spoke with study co-author Jane Kim, assistant professor of health-decision science at the Harvard School of Public Health, about why there is so much conflicting information about how the HPV vaccine should be used, and what researchers still don't know about it. Excerpts:

NEWSWEEK: What's your recommendation for parents of young girls who are considering the vaccine?
Jane Kim: This type of analysis is not really equipped to help inform individual decision-making. What we're trying to do is help policy decision making. From a population standpoint, we found that vaccinating preadolescent girls, prior to sexual activity, is a good value for the money.

It seems it may not be as cost-effective to vaccinate older girls who are already sexually active. Why not?
The vaccine is not beneficial for women who already have HPV. Once you start sexual activity, HPV is so prevalent. We're looking at a whole population of 26-year-olds. At that age, most females are sexually active. Their chances of having been exposed to one of the [virus] types increases with age. We find diminishing health benefits.