Healthy Skepticism Library item: 9958

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Publication type: news

Gram K.
Controversial vaccine
The Vancouver Sun 2007 May 2
http://www.canada.com/vancouversun/news/westcoastnews/story.html?id=2997f393-78cd-49c0-ad93-3c3ae3e934c9&p=4

Full text:

Many researchers say that Gardasil will not eradicate cervical cancer — not even guarantee protection from the virus —but that’s not stopping women from getting the three-shot treatment

Michelle Conrad didn’t hesitate for long when her doctor told her about a vaccine that could protect her from cervical cancer. Her mother died of the disease 18 months ago, when Conrad was 20 years old.

Now 22, she faced her fear of needles, rolled up her sleeve and got the last of the three-injection vaccine, called Gardasil, at the end of April.

She says she feels safer, especially since she has seen several family members get various forms of cancer.

“My dad and I discussed it and decided it would be a good idea for me to get vaccinated against it,” she says, adding that she thinks the vaccine should be available to all girls, regardless of their ability to pay the $405 cost.

She wishes it had been around for her mother.

“It would have been nice if it had been around when I was nine, too.” she adds.

Many people agree with Conrad’s contention that the Gardasil vaccine should be made available free to all girls. Many others disagree.

Ever since last October, when Health Canada approved the vaccine for females aged nine to 26, support for its use has been spreading like an infectious disease.

In just three months — the speed of light in Ottawa’s bureaucracy — the federal government announced it will contribute $300 million toward inoculating Canadian girls.

Since that announcement, three provincial governments, Prince Edward Island, Nova Scotia and Manitoba, have committed to school-based vaccination programs to start this year. All the other provinces, including B.C., are actively considering such programs.

But claims that the vaccine will radically alter the cervical cancer landscape in Canada are generating widespread controversy.

There is no denying that the notion of a vaccine against cancer is attractive, says a U.S.-based cervical cancer researcher who has spent 10 years working on the vaccine produced by the Merck Frosst pharmaceutical company.

“No politician wants to be quoted as saying, ‘I wouldn’t support a vaccine that prevents cancer in women,’” says Diane Harper, a top-level scientist and professor at Dartmouth Medical School in New Hampshire, who has led clinical trials of the vaccine and written widely on the topic. “That is just too powerful a political statement.”

NO GUARANTEE

But Harper warns that Gardasil will not eradicate cervical cancer. Not even close. It doesn’t even guarantee protection from the virus that causes cervical cancer.

It’s very effective, nearly 100 per cent, against the two strains of a common sexually transmitted virus called human papillomavirus or HPV that cause 70 per cent of cervical cancers, as long as the virus isn’t present when the immunization occurs.

But annual pap smears will still be necessary to screen women for the other 30 per cent of the viruses.

“It’s not going to eliminate a disease category, and it’s not going to eliminate cervical cancer precursors,” she says.

“That means we will still have hundreds of thousands of women who are vaccinated who are getting their pap smears who will still have cancer precursors,” she says “That part is being lost on people.”

A second vaccine, made by Glaxo-Smith Kline will soon be approved. It is slightly different from Gardasil, because it doesn’t protect against genital warts. But it also only immunizes against the same two strains of the virus.

Another difficulty is that since Gardasil has only been tested for five years, no one knows how long it will last before it needs a booster. And because cervical cancer can take 20 years to develop, no one knows how effective it will actually be against cervical cancer. They can only surmise.

“We think this is a promising development, but it’s definitely not a panacea,” says Barbara Kaminsky, CEO of the B.C. Cancer Society.

There are more than 200 strains of the HPV virus, some of which cause genital warts and some of which cause cervical cancer. Eighty per cent of adults with healthy immune systems can expect to get it at least once in their lifetimes.

Condoms provide imperfect protection, because it spreads by skin-to-skin contact. Usually it clears up by itself, leaving no evidence it was ever present.

But in 10 to 25 per cent of cases, the virus persists, eventually causing detectable abnormalities on the cervix. In 98 per cent of these cases, the abnormalities are caught by a pap smear and treated.

However, less than one per cent are missed and they can, over five to 20 years, cause cervical cancer, the only known cancer to be caused exclusively by a virus.

Physicians in the field are thrilled to have it. Oncologists, gynecologists, obstetricians, public health officials and cancer agencies all have publicly endorsed it. The latest to announce support was the Canadian Pediatric Society.

Dianne Miller, a Vancouver gynecological oncologist and the head of the B.C. gynecological tumour group, which makes recommendations to the government, says she never dreamed a vaccine would exist during her career.

“This is a major advance in cancer prevention,” she says. “This is the first time in our history that we have the ability to actually truly prevent a cancer.”

But Alan Cassels, a pharmaceutical policy researcher at the University of Victoria and a father of a 10-year-old girl, says with only five years of testing and many examples of vaccines being either recalled or withdrawn from the market due to safety concerns, he’s in no rush to have his daughter vaccinated for HPV. He says he feels the same way about everyone else’s daughters too.

NOT SATISFIED

Cassels points out that even the U.S. Food and Drug Administration is not satisfied that Merck Frosst has proven it’s safe for young girls. While it approved the vaccine, the FDA demanded more study be done on its safety for 11- to 12-year-old girls.

“My 10-year-old is not going to be one of your test subjects,” Cassels says. “We don’t know the long-term effects. We don’t even know if it provides protection past five years.”

Cassels says he isn’t opposed to vaccines on principle. A former Canadian naval officer and UN peacekeeper, Cassels has been immunized dozens of times himself and ensured his children were vaccinated for the basic childhood diseases. But the HPV vaccine is different, he says.

“When there are a lot of unknowns, it makes sense to adopt a precautionary approach.”

Harper agrees there are a lot of unknowns. She doesn’t think anyone should get the vaccine without understanding that women may need a booster in 10 years and annual pap smears. According to most estimates, boosters will cost about $100 per shot.

Harper says that while the vaccine won’t eliminate the disease, it will reduce the emotional costs of a precancer diagnosis and the financial costs of early treatment.

She says the real burden of the disease in Canada and the U.S. is not the number of cancers, it’s the number of people with the abnormal screens.

While about 150 B.C. women die of cervical cancer annually, more than 40,000 have abnormal pap screen results. At the very least, those women will need to return six months later for a second pap smear. Most will have resolved on their own, but about 10,000 will require a further visual exam called a colposcopy, and about 3,000 of those will be diagnosed with precancerous lesions and be treated.

B.C. Cancer agency’s Miller says preventing the abnormal screens is reason enough to ensure all girls get it.

“We put a huge amount of resources currently, into the prevention of cervical cancer. But all of those resources are put in after the horse is out of the barn because the woman has already become infected with the HPV virus just from being sexually active,” she says.

“In the long run it’s going to save a lot of women a lot of grief.”

But critics of a widespread immunization program say the pap screening program in place is very effective and over 50 years has caused a 74-per-cent decline in the number of cervical cancers in the U.S.

Abby Lippman, a professor of Epidemiology at the McGill University and the Chair of the Canadian Women’s Health Network, says health care dollars can be better spent targeting the women who are not getting regular pap smears and reducing the number of false positive test results.

GOVERNMENT RUSHING

Hans Krueger, a B.C.-based health economist, says he thinks governments are rushing into an expensive and potentially not very effective program without thinking it through.

“There is no crisis here,” he says. “Canada has the best cervical cancer rates in the Americas and B.C. is tied with Quebec for the best rates in Canada.”

In 2006, 390 Canadian women died of cervical cancer and 1,350 were diagnosed. By comparison, breast cancer claimed 5,300 women last year and lung cancer took 8,600 women.

“When you look at the comparative numbers, we’re thankful cervical cancer is not as big an issue as other cancers,” says Kaminsky, adding that the federal funding of $300 million is about one-sixth of what would be needed to vaccinate Canadian girls.

Cassels says scientists have said for many years that the risk of cervical cancer increases the more sexually active a woman is.

“If you are relatively monogamous and practice relatively safe sex and get an annual pap smear, you are in a much lower risk category,” he says.

“When you change the level of risk, you change the benefit/risk ratio. If you are high risk, you would be willing to take the vaccine, but a lower risk changes the equation. They aren’t getting enough protection to warrant the unknowns of the vaccine.”

Cassels says that while Merck has developed some good drugs, its recent history hasn’t been good.

“This is the same company that brought us Vioxx [the withdrawn painkiller linked to heart attacks and strokes],” he says.

He says he fears governments are blinded by fear of cancer when they opt into a universal HPV vaccine.

Certainly, if state, provincial and federal governments purchase enough vaccine to immunize their populations, Merck will make a ton of money. Some analysts believe Gardasil’s annual sales could reach $2 billion or more by 2010.

At $405 Cdn for the three-shot vaccine and an estimated $100 for each booster, the vaccine is not cheap for individuals to pay for on their own.

But it gives women like Michelle Conrad, a young, sexually active woman who knows she still needs annual pap smears and who is willing to pay the price for the vaccine (actually her father paid), a new tool in their tiny arsenal against cancer. But what does it give a nine-year-old?

Many analysts, including Krueger and Cassels worry that if governments add the vaccine to the school-based immunization program, girls will assume they have 100-per-cent protection and stop getting screened. That could actually cause a rise in cancer rates.

“There is time to think about this,” says Kreuger. “Someone needs to put up some caution and ask these questions.”