NO SOONER HAD THE INK DRIED on Governor Rick Perry’s executive order to require all sixth-grade girls in Texas to be vaccinated for human papillomavirus ( HPV)—the cause of deadly cervical cancer— by next school year than a firestorm erupted in our newspapers, blogs, and the halls of the Capitol. The initiative, the first of its kind in any state, contained three terms that tend to make many Texans uneasy: “vaccine,” “sexually transmitted disease,” and “cancer.” Then came “government,” “mandate,” and “sixth-graders,” and all hell broke loose. By now you’ve heard every shade of the rhetoric: On the upside, Perry’s order pioneers a cancerless future for all women; on the downside, it violates parental rights, might encourage promiscuity, and represents a shady relationship with Merck, the vaccine’s producer. You’ve also witnessed some of the fallout: A House bill has been filed to rescind the mandate, Merck is halting its lobbying efforts, and, oh, there’s a lawsuit against Perry. But amid all this hoo-ha, you’ve probably heard little (or little that’s clear-cut, anyway) about the actual science involved. What is the HPV vaccine, really? Here’s a look at one of the most important public health initiatives promulgated by Texas in recent memory.
First things first. What is HPV and how does it cause cervical cancer?
HPV is actually a collection of about one hundred viruses, thirty of which are passed via sexual contact. Of those thirty, two cause 70 percent of cervical cancers (an additional eleven viruses are responsible for the rest), and two others cause 90 percent of genital warts. The remaining, non-sexually transmitted viruses are passed by other human contact—say, shaking hands—and are generally asymptomatic, though some can result in warts on the hands and feet. The viruses apparently derange the DNA in the epithelial cells of certain mucosal tissues, principally those of the cervix, vagina, and anus, thus causing cancer. HPV is the most common sexually transmitted disease in the U.S.—it generates about six million new infections a year—and it is estimated that 20 million Americans (men and women) carry an active infection at any given time. Seventy-five percent of women will have some form of the virus during their lifetime.
How is cervical cancer normally detected?
With an annual Pap test. Since its introduction in the fifties, this screening for HPV and its precancerous cells has reduced the incidence of mature cervical cancer by 75 percent. A Pap catches cancers from all HPV strains—no woman should forgo one, as unpleasant as it may be—but it’s not a cure or a prophylactic. Which is why Merck’s vaccine (as well as one anticipated from Glaxo-SmithKline next year), which targets the four most pathogenic viruses, has public health officials so excited.
So what is this vaccine?
Available since last June, it’s called Gardasil—and it is not, as you might have read on some blog, composed of live HPV. Merck produces it by transferring the genes that contain the code for certain key proteins in those four viruses to yeast, where they express said proteins, and then by suspending these in an injectable fluid. Once integrated into the body’s physiology, these proteins train the immune system to recognize and destroy the viruses. The vaccination requires three shots over a six-month period; the company’s best guess is that it will be effective at least four years.
How about the cost? I’ve read that Gardasil is prohibitively expensive.
Merck claims that 96 percent of health insurance carriers cover it, but predictably, it’s not that simple. Many pediatricians have complained that insurers are not reimbursing them sufficiently to make it worth their while to stock the vaccine, a complaint they’ve had about other vaccines as well. So some have refused to buy the stuff, while others are charging a premium: The three shots cost $360, but a patient may have to pay upward of $450 to cover storage and office costs. Those families who qualify for Medicaid can obtain the vaccine free