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Canadian Researcher Slams Move for Mass Vaccination Against Cervical Cancer

by Medindia Content Team on  August 6, 2007 at 12:19 PM Cancer News   - G J E 4
Canadian Researcher Slams Move for Mass Vaccination Against Cervical Cancer
Merck's Gardasil vaccine against the human papilloma virus (HPV) is becoming the rage these days in North America.

The shot is targeted against the four strains (out of 15) of HPV that are thought to trigger 70 percent of cervical cancers.
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The cervix is the lower part of the uterus (womb). The upper part, or body, of the uterus, is where a fetus grows. The cervix connects the body of the uterus to the vagina (birth canal). The part of the cervix closest to the body of the uterus is called the endocervix. The part next to the vagina is the ectocervix. Most cervical cancers start where these 2 parts meet.

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The human papilloma viruses (HPVs) are a group of more than 100 different types of virus. They are given numbers to distinguish them. HPV's can be transmitted through intimate contact, including sexual intercourse. Some of the HPV viruses can cause genital warts - those numbered HPV 6 and HPV 11. These two are sometimes called low risk because they are not associated with cervical cancer.

Since its approval for use in girls and women between the ages of 9 and 26 by the U.S. Food and Drug Administration last June, several states have moved to mandate Gardasil's inclusion into routine school vaccination programs.

That's because vaccinating before the onset of sexual activity is most effective in preventing HPV infection, it is believed.

In Canada the federal government has announced a $ 300 million immunization plan.

Premier Dalton McGuinty of Ontario has unveiled a $117-million three-year program, the HPV vaccine, Gardasil, will be offered to approximately 84,000 girls. The vaccinations will be administered by public health nurses in schools.

In June, Nova Scotia became the first province in Canada to announce it would begin HPV vaccinations.

But what is the rush, wonders Abby Lippman, a professor in the department of Epidemiology, Biostatistics and Occupational Health at McGill University in Montreal.

In a commentary published online in the Canadian Medical Association Journal on Wednesday, a group of experts led by Lippman said the reported vaccine trials of Gardasil, manufactured by Merck had been funded wholly, or in part, by the manufacturer.

She says only 1,200 girls aged 9 to 15 were enrolled in clinical trials of the vaccine and the youngest were only tracked for 18 months. "Clearly, this is a thin information base on which to construct a policy of mass vaccination for all girls aged 9 to 13," states the report.

As well, the vaccine is expensive, selling for $404 for the three required doses, said Lippman, and cost-effectiveness analyses of proposed vaccination programs needed to evaluate the expense are missing.

Lippman wants a thorough governmental review of the vaccine's safety, cost and uses before a large-scale immunization program is initiated.

And she suggested certain programs, such an immunization registry, be established to track patients, should the first round of vaccinations prove ineffective and follow-up immunizations be warranted.

Without a public education campaign, misunderstandings about the vaccine could lead teenagers to practice unsafe sex, Lippman says.

Lippman said women should be reminded that cervical cancer is "not an epidemic," leading to the deaths of approximately 400 women a year — a number that is declining, according to the report.

It also notes that cervical cancer is the 11th-most frequent cancer affecting Canadian women and 13th-most common cause of cancer-related deaths.

As well, she said, HPV does not necessarily lead to cancer.

"Most HPV infections are cleared spontaneously, within one year for about 70 per cent of women and within two years for 90 per cent. Cervical cancer will not develop in most women who are infected with even a high-risk strain of HPV," said the report.

The article stated that women will also still have to use safe-sex practices, and get annual Pap smears that detect abnormal cervical cells that could signal cancer.

In a Pap smear test, the doctor or nurse uses a plastic or metal instrument, called a speculum, to widen the vagina. This helps the doctor or nurse examine the vagina and the cervix, and collect a few cells and mucus from the cervix and the area around it. These cells are placed on a slide and sent to a laboratory to be checked for abnormal cells.

Experts fear that this Gardasil vaccination could mislead people into thinking that Pap test is unnecessary whereas even the World Health Organisation (WHO) has stressed early detection is a must in the fight against cervical cancer even after vaccination.

Gardasil is not a magic bullet, Lippman stressed.

So why is the federal government paying for such a vaccination program?

"Some people are going to profit by this," said Lippman.

As well, she noted that a new vaccine produced by GlaxoSmithKline, Cervarix, will be entering the market next year.

"Maybe that will be better for Canada. We don't know that," she said.

Besides some conservative groups worry the vaccine will encourage sex among young people, while other critics view the mandates as an intrusion on parental rights year.

Source: Medindia
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