This afternoon, Katie Couric ran a long segment on her daytime talk show, Katie, about what she called the “controversy” over the vaccines against human papilloma virus, or HPV, an infection that causes cervical, throat, penile, and anal cancers. She featured one mother who says that Gardasil, the HPV vaccine made by Merck , killed her daughter, and a young woman, seated with her mother, who said that Gardasil had caused years of illness that made her think she might die. (GlaxoSmithKline GSK +0.15% makes another HPV vaccine, Cervarix, that is less commonly used in the U.S.)
Alongside those stories, Couric also featured two medical experts: Dr. Diane Harper, the chair of family and geriatric medicine at the University of Louisville, who helped test Gardasil but has since argued that the vaccine has been over-marketed and its benefits oversold; and Mallika Marshall, a Harvard Medical School doctor who is Couric’s in-house medical correspondent. Marshall defended the vaccine; strangely, only her arguments appear on the show’s Web site.
Despite the attempt at balance, I think most viewers will be left with the impression that the vaccine is dangerous and that its benefits don’t outweigh its risks – a conclusion that is not shared by the American Academy of Pediatrics, the American Academy of Family Physicians, the American College of Obstetricians and Gynecologists, or the Centers for Disease Control & Prevention.
Here’s how Couric stacked the deck against the HPV vaccine:
1. By downplaying the effectiveness of the vaccine: Harper argued that HPV vaccines offer only short-term protection, lasting just five years. This elicited a shocked reaction from Couric – understandably. Why would national guidelines recommend that 11-year-old girls and boys get a vaccine that wears off by the time they are sixteen?
But the statement isn’t true. It’s more true to say that the vaccine’s effectiveness can only be measured using the data we have so far, which at one point was only five years. A recent analysis of 4,900 women in Nordic countries, which use more robust medical records systems than the United States, found Gardasil “is effective up to 6 years following vaccination with a trend of continuing protection up to 8 years following vaccination.” A second analysis, conducted by Merck, also indicates that people still have immune responses 8 years after getting the shot.
“The antibody levels would indicate that immunity is going to be for many, many years beyond five years,” says William Schaffner, a professor of preventative medicine at Vanderbilt Medical School. “We don’t know for how long.”
It’s possible that Gardasil could offer lifetime protection; or patients may need a booster shot. HPV is also different than many other infections, because it takes decades to cause cancer, so protection over the short term may actually be enough.
2. By overplaying the power of Pap smears: Harper also argued that the combination of Pap smears and HPV DNA testing could catch all cervical cancer cases – she said they were 100% accurate. The tests are really incredibly accurate, and women should get them regardless of whether or not they have had the HPV vaccine. But nothing is perfectly effective, and some women will fail to get regular screening, so a vaccine may still help. “That’s a remarkable statement because that is incorrect,” says Schaffner. “She overstated the case enormously.”
3. By underplaying the risk of cancer: Harper dismissed other cancers caused by HPV as extremely rare, implying that they shouldn’t be part of a risk-benefit calculus about the vaccine. But that’s not fair. Between 2004 and 2008, the CDC estimates that there were 11,967 cases of cervical cancer caused by HPV each year and 11,726 cases of head and neck cancer, meaning they could be seen as equally big problems. Work by authors including Maura Gillison of Ohio State University, a pioneer in studying the HPV/throat cancer link, indicates that by 2025 HPV throat cancer will be more common than cervical cancer, thanks largely to pap smears and HPV DNA tests. The CDC estimates that HPV causes 26,000 cases of different cancers each year.
A caveat: use of HPV vaccines to prevent head and neck cancer has not been approved by the Food and Drug Administration, and it probably never will be, because the studies would be too difficult to conduct. In cervical cancer, researchers could look for precancerous lesions; these are harder to detect in the tonsils, where throat cancer starts.
4. By pulling viewers’ heartstrings: Couric told moving stories about vaccine risks using live interviews with people who said they had been harmed. Defenses of Gardasil were offered in dry platitudes. There were no interviews with people who suffered from cancer that might have been prevented by the vaccine.
I started writing about the link between HPV and throat cancer in 2009. Generally speaking, head-and-neck cancer caused by HPV is less deadly than other types of head-and-neck cancer. But the patient I spoke to for that story – an economist named Martin Duffy who had run 40 consecutive Boston marathons – was killed by his disease. “I made my living as a public speaker,” he told me before he died. “Now I sound like Daffy Duck.” Without his voice, he asked, “How do you tell the people that you love you love them?”
We can’t ignore the stories of the girls Couric reported on, either. She said that eleven cases allege that HPV vaccines have caused death, according to the National Vaccine Information Center, an anti-vaccine group. (For comparison, Merck has shipped 62 million doses of Gardasil.) Vaccine makers and the CDC should redouble their efforts to make sure that if there is a risk of death from the vaccine, we know that. I think Merck in particular should be making an effort to approach these families and find out if there is anything it can learn about its vaccine. Is there any biologically plausible way that Gardasil could be having these effects? It seems unlikely, but we can’t be careful enough.
But deaths – including deaths by seizures or unexplained causes – do occur for all sorts of reasons, without explanation, and just because a death happened 18 days after a vaccine was given, as in the example on Katie’s show, does not mean the vaccine caused it. So far, investigations trying to link Gardasil and Cervarix to serious side effects have come up empty.
A study of 997,000 girls in Nordic countries found no link to autoimmune, neurological, and venous thromboembolic adverse events from the vaccine. A CDC analysis published in the Journal of the American Medical Association in 2009 also found no link between HPV vaccines and serious side effects. Schaffner says the main side effects he sees are sore arms and fever.
So far, despite the fact that many families do opt not to get the vaccine, Gardasil is performing better than expected. In the seven year period ending in 2010, the prevalence of HPV infection in girls and women fell 56% to 5.1% of the population. Thomas Frieden, the director of the CDC, told NBC the reduction was “better than we hoped for.” Let’s hope that can continue.
* This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.