WHITEHOUSE STATION, N.J. — Add to the list one more thing parents have to worry about this back-to-school season. Tens of thousands of schoolgirls will be offered free shots of a controversial new vaccine against cervical cancer this year.

Rolled out in June 2006 by Whitehouse, N.J.-based pharmaceutical giant Merck &Co., the Gardasil vaccine against the human papillomavirus (HPV) believed to cause cervical cancer was hailed as the first-ever anti-cancer shot.

But controversy has circled since its launch, especially this summer after the possibility was raised that it may be a killer: Three young women have died following injections of the vaccine.

And 1,637 reactions reported to the FDA by last May also include paralysis, spontaneous abortion with fetal anomalies and disturbed menstrual cycles, raising questions about the vaccine’s impact on fertility.

Some view Gardasil as a giant step forward in the fight against cervical cancer, which affects 12,000 women annually, and, though highly treatable, still claims 4,000 lives every year.

While 20 million Americans have an HPV infection — generally acquired through sexual contact — most go unnoticed and clear spontaneously within a year. A fraction of infections among women, however, if untreated develop eventually into cervical cancer.

Gardasil specifically targets four of about 100 known HPV strains. Clinical trial data suggest it virtually eliminates the risk, in the short-term, of two strains believed responsible for about 70% of cervical cancer cases.

To date, most of the 10 million doses distributed globally have been targeted at 9- to 26-year-old Americans.

Virginia mandates Gardasil for all girls entering the sixth grade. The Texas Legislature revoked a similar mandate implemented in February by Gov. Rick Perry’s executive order, following revelations about the governor’s ties to Merck-affiliated lobbyists and campaign funding from the vaccine manufacturer.

Altogether 41 states have introduced legislation to mandate, fund or educate about HPV vaccination, and at least 17 states have begun to make it available already.

The HPV vaccine is a major moneymaker for Merck &Co. In July, the company reported Gardasil generated $358 million for the quarter. For the year, Gardasil sales are projected to exceed $1 billion.

‘No Epidemic’

But medical concern abounds, especially about the drive to make the vaccine broadly available to young girls. A paper in the Aug. 28 issue of the Canadian Medical Association Journal said there is “no epidemic of cervical cancer in Canada to warrant the sense of urgency for a vaccination program.”

Canada’s federal finance minister has devoted an initial $300 million to promote the vaccine for all 9- to 26-year-olds. And starting this fall, the government of Ontario will offer free vaccines to Grade 8 girls in a $39 million provincial vaccination program targeting 84,000 students.

The Canadian medical journal’s lead researcher, McGill University epidemiologist Abby Lippman, reviewed the literature available on the HPV vaccine and concluded it “reveals a sufficient number of unanswered questions to lead us to conclude that a universal immunization program aimed at girls and women in Canada is, at this time, premature and could possibly have unintended negative consequences for individuals and for society as a whole.”

In the United States, “unintended negative consequences” have already occurred. Of the 1,637 side-effects reported to the FDA as of May 11 and obtained in June through the Freedom of Information Act by the Washington-based group Judicial Watch, 77% were classified as “non-serious” — mostly vomiting, sore arms and fainting.

One woman crashed her car into another vehicle when she blacked out after a shot. Two broke their noses falling on their faces after innoculations.

Other “non-serious” events included movement disorders, whole body rashes and arthritic joint pain.

Serious events included the blood-clot death of a vaccine recipient just three hours following a Gardasil injection and the heart-failure deaths of a 19-year-old and 12-year-old. Another 20-year-old was hospitalized with myocarditis (inflammation of the heart muscle).

As well, a dozen cases of Guillain-Barré paralyzing syndrome, which can be fatal and can leave patients permanently weakened, were reported before May 11, as well as grand mal seizures, temporary blindness and facial paralysis.

One 13-year-old awoke the day after a Gardasil injection unable to shut her right eye. A 19-year-old couldn’t spit her toothpaste or smile the next morning.

Rhonda Vega thought the Gardasil vaccine being offered at her daughter’s Gardnerville, Nev., school was a good idea — especially because her own grandmother had died of cervical cancer. But eight days after 14-year-old Jessica received a dose of Gardasil, her legs began to feel numb while she was in geography class May 10.

“She could barely walk when we took her to the car,” said Vega, who rushed Jessica to the hospital where her legs and arms quickly became paralyzed. A harrowing week ensued of watching to see if the Guillain-Barré syndrome she had acquired would kill her. In August, she was still recuperating from the lingering effects of the paralysis.

“The state health authorities said the vaccine had nothing to do with Jessica’s illness because Merck [the vaccine’s manufacturer] did not list Guillain-Barré as a side-effect,” said Vega.

But a new patient information packet subsequently issued by Merck in July specifically mentions Guillain-Barré syndrome as a reported side effect, “as with all vaccines,” according to the manufacturer.

“Just how quickly these events are occurring after [anti-HPV] vaccination is extremely worrisome,” said retired Jackson, Miss., neurosurgeon Russell Blaylock, associate editor of the Journal of American Physicians and Surgeons. “It suggests there is a very powerful immune adjuvant (a chemical or metal like aluminum added to spur the immune system to activity) causing an intense immune system response.”

Said Blaylock, “If this vaccine were made mandatory, the number of paralyses and girls with serious neurological damage would just be astronomical.”

The FDA also received reports on 42 pregnant women who were accidentally vaccinated with Gardasil, which Merck specifically advises against. Of those, 18 spontaneously aborted, some with confirmed fetal anomalies, and eight surgically aborted their babies. Outcomes of the other 16 pregnancies are unknown.

Additionally, at least two dozen cases of disturbed menstrual cycles were reported, with prolonged or absent bleeding.

But Dartmouth Medical School professor Diane Harper, lead researcher of Merck’s clinical HPV vaccine trial, thinks the vaccine is as safe as any other.

Harper said that the side-effects reported to the FDA are difficult to interpret, in terms of assessing Gardasil’s relative danger.

“We don’t know the denominator — that is, how many received the shot — to determine a true incidence of adverse events,” she said.

With respect to inducing abortions, Harper noted that 40 accidentally vaccinated pregnant women in the drug trials showed the same miscarriage rates as 41 other pregnant participants who received an aluminum-containing placebo.

“Disturbances to menstrual cycles and fertility are particularly hard to gauge,” she said, “because they are so easily disrupted by other phenomena.”

But Harper also acknowledged that vaccine reactions in general are under-reported because of “disincentives to report.”

“Doctors are so busy, and to call up and report, particularly if it’s not life-threatening, is just a real hassle,” Harper said. “And once they do, they’re sort of ‘on the hook’ to provide further information.”

Merck spokesman Jennifer Allen pointed to trial data showing the vaccine did not affect the fertility of rats.

McGill University researcher Lippman and her colleagues were especially troubled by the lack of data on the vaccine.

“To date, only a handful of randomized controlled trials of sufficient quality have been reported. Interestingly, all … were funded in whole or in part by the vaccine’s manufacturer,” their Canadian Medical Association Journal paper stated.

Especially worrisome, the researchers said, was the “thin information base” available on the safety and effectiveness of the three-shot Gardasil regimen for younger girls aged 9 to 15.

Merck-sponsored researcher Harper agreed that Gardasil shouldn’t be given to minor girls. Because of the low likelihood of young girls being exposed to HPV, and since most cervical cancers develop in women beyond 40, Harper favors limiting the vaccine to women over 18.

“Personally, I think we’ve really gone down the wrong road promoting this vaccine for younger girls,” she said. “We don’t know how long the vaccine’s protection will last.”

Celeste McGovern is based in Innerleithen, Scotland.