Mon September 19, 2011
HPV Vaccine: The Science Behind The Controversy
The first vaccine against human papillomavirus, or HPV, which causes cervical cancer, came out five years ago. But now it's become a hot political topic, thanks to a Republican presidential debate in which candidate Michelle Bachmann inveighed against "innocent little 12-year-old girls" being "forced to have a government injection."
Behind the political fireworks is a quieter backlash against a public health strategy that's won powerful advocates in the medical and public health community.
It appears this vaccine gets people riled up because it involves sex and 11-year-old girls.
The two approved vaccines, Gardasil and Cervarix, are designed to protect against a sexually transmitted virus. That's why Julie Stewart was shocked when the pediatrician said her 11-year-old Sophie should get it.
"My daughter is so not-sexually-active that it seems very premature to even think about protecting her from cervical cancer," Stewart says.
Stewart says she tends to have faith in doctors. So she pondered why she reacted that way.
"I realize it's probably more about my squeamishness with the thought of her becoming sexually active than the vaccination itself," she says. "It's not the science. I think it's my own issues around her developing sexually."
Stewart lives in Washington, D.C., which requires the vaccine for middle-school girls. Virginia is the only other place to mandate it. Both let you opt out with a doctor's note. Dozens of other states are debating whether to mandate the vaccine.
The Case For Fighting Cervical Cancer
Many find the public health case for HPV vaccination compelling. Cervical cancer strikes about 12,000 US women a year and kills around 4,000. Strong backers of the vaccine include the American Academy of Pediatrics, the American Academy of Family Practitioners and the Centers for Disease Control and Prevention.
The vaccine requires three shots over six months and costs upwards of $400, which is not always covered by insurers or government agencies.
Milwaukee pediatrician Rodney Willoughby, a designated spokesman for the American Academy of Pediatrics, says there's a very good reason for the big push to get pre-teen girls vaccinated. The idea is to get it done well before their first sexual encounter.
"This is being timed just before you start to have those discussions about the birds and the bees," Willoughby says.
Studies done before widespread HPV vaccination show that by the time they're 15, nearly 10 percent of American girls are infected with HPV. By age 17, that's doubled to nearly 20 percent.
Some research also indicates that many parents are clueless about when their children start having sex.
"Ideally none of our children is going to be sexually active until they meet Mr. Right or Mr. Wrong, and that's the end of the story," Willoughby says. "But it happens, and sometimes you're not aware of it. And we can't prevent [HPV infection] once that exposure's occurred."
Willoughby says his daughter will get the vaccine next year, when she turns 11.
A Lobbying Effort From Manufacturers
But Dr. Diane Harper, a professor at the University of Missouri-Kansas City School of Medicine, says the vaccine is being way over-sold.
That's pretty striking, because Harper worked on studies that got the vaccines approved. And she's accepted grants from the manufacturers, although she says she doesn't any longer.
Harper changed her mind when the vaccine makers started lobbying state legislatures to require schoolkids to get vaccinated.
"Ninety-five percent of women who are infected with HPV never, ever get cervical cancer," she says. "It seemed very odd to be mandating something for which 95 percent of infections never amount to anything."
By Harper's calculations, the tried-and-true method of regular Pap smears is a more effective way to prevent cervical cancer than the vaccines. "Pap smear screening is far and away the biggest thing a woman can do to protect herself, to prevent cervical cancer," she says.
Of course, cervical exams and Pap smears are not universally done, they're invasive, and when the test comes up abnormal, the woman faces cervical biopsy and possibly an unpleasant procedure called colposcopy to obliterate pre-cancerous growths.
Apart from the comparative advantages of vaccine versus Pap smears, Harper has another objection to mandating early vaccination at this point. She points out that studies so far show the vaccines protect for four or five years. Scientists hope protection will last for 10 years or more, but it's possible young women may need a booster shot later.
As it stands now, Harper says, vaccinating an 11-year-old girl might not protect her when she needs it most – in her most sexually active years.
A Dangerous Vaccine?
There's another reason parents balk. Some worry the vaccine could be dangerous.
Two children have died of a rare neurological disorder – an early and accelerated form of ALS, or Lou Gehrig's disease – after getting the vaccine.
Last month, the independent Institute of Medicine found no good evidence that these deaths, or any other serious side effects, were cause by the vaccine.
The CDC has examined 35 deaths that occurred among 35 million young people who received the vaccine. It also concluded there is no evidence of cause-and-effect.
"We have not identified a significant likelihood of serious adverse events following vaccine," says Dr. Joseph Bocchini, chairman of pediatrics at Louisiana State University in Shreveport, who chairs CDC's working group on HPV vaccines. "This is a very safe vaccine."
But as much as he believes in the vaccine, Bocchini doesn't think the government should require kids to get it yet.
"We want to get some experience with it," he says. "We want to educate physicians and other providers about the benefits of the vaccine. We want to educate the public about the infection and its consequences."
So for now, the CDC's lead advisor thinks the decision should be left to parents.
Some parents, like Dr. Willoughby, will go ahead and get it. "If in 20 years time, my daughter, with two children at home, develops cervical cancer, and I didn't give her the vaccine, I'm going to be looking pretty hard in the mirror at myself," he says.
And some parents, like Julie Stewart, will think about it some more.
"Our doctor plans to talk to us about it at my daughter's 12-year wellness visit," Stewart says. "So, you know, maybe we'll do it then."
For her, it's not really a question of whether. It's a question of when.