Lawmakers looking to force preteen girls to take Gardasil, a new vaccine against a virus that causes cervical cancer, are targeting the wrong age group, cancer data shows.
Middle-school girls inoculated with the breakthrough vaccine will be no older than 18 when they pass Gardasil’s five-year window of proven effectiveness — more than a decade before the typical cancer patient contracts the sexually transmitted human papillomavirus (HPV).
Infectious disease specialists and cancer pathologists say the incubation period for HPV becoming cancer is 10 to 15 years — meaning the average cervical cancer patient, who is 47, contracted the virus in her 30s and would not be protected by Gardasil taken as a teen.
“It is a delicate balancing act,” said Debbie Saslow, director of breast and cervical cancer control at the American Cancer Society. “If the vaccine is given at too young an age, it may wear off. Yet if it is given too late, it won’t work.”
Merck & Co. is still studying the longevity of Gardasil, the lone HPV vaccine on the market, which won approval from the Food and Drug Administration in June. But that hadn’t impeded its lobbying efforts. Legislators in at least 20 states and cities, including Virginia and the District of Columbia, are considering HPV vaccinations for girls 11 to 13 as a requirement for school attendance. Texas already has done so.
“We are doing further tests and follow-up. But right now, we know it is effective for five years,” said Dr. Richard Haupt, executive director of medical affairs in Merck’s vaccine division.
Gardasil, a $360 series of three shots over six months, protects against two HPV strains that cause nearly 70 percent of cervical cancer cases. It also prevents two other strains linked to 90 percent of genital warts cases.
Merck, which did not respond to repeated requests for its HPV incubation statistics, unexpectedly suspended its lobbying campaign yesterday.
“Our goal is about cervical cancer prevention. … We’re concerned that our role in supporting school requirements is a distraction from that goal,” Dr. Haupt told the Associated Press.
By the numbers
Dr. Joseph Bocchini, chairman of the committee on infectious disease of the American Academy of Pediatrics, says HPV can take up to 20 years to cause cervical cancer.
“It can occur more rapidly, but very commonly, it is a 20-year period before it leads to cancer,” said Dr. Bocchini, whose group has endorsed HPV vaccinations on 11- and 12-year-olds but has withheld support for its mandated use.
Even when applying a longer 20-year incubation period, requiring Gardasil for sixth-grade girls, as nearly all the legislation does, would not prevent the overwhelming majority of cervical cancer cases in the U.S.
American Cancer Society numbers show that from 2000 to 2003, more than 70 percent of cervical cancer patients were older than 40 — still outside Gardasil’s five-year protection window if given to sixth-graders.
Merck is working on a booster shot to extend Gardasil’s five years of protection.
“We are aware of some evidence of immune memory. But if a booster shot is necessary, it would likely be another dose of Gardasil,” Dr. Haupt said.
None of the HPV vaccine legislation being considered addresses the potential for booster inoculations that could fall outside the enforcement mechanism — rules that bar students from school unless they have the required shots.
Vaccine boosters vary in longevity. A hepatitis B booster is required every 10 years, while others can provide lifelong immunity.
Lawmakers pushed HPV legislation to the fast track after the Advisory Committee on Immunization Practices, run by the Centers for Disease Control and Prevention, in July endorsed such an inoculation for girls 11 to 12.
“The point in vaccinating kids 9 to 12 is not to reduce number of cases found in that age group, but to vaccinate prior to beginning sexual activity,” said CDC spokesman Curtis Allen. “The benefits of the vaccine decrease as women age because they are more likely to have already been infected by one of the HPV strains.”
Seventy percent of females are sexually active by age 18, according to the CDC.
But based on cancer statistics, cervical cancer incubation periods, and the five-year life-span of Gardasil, state lawmakers — who have billed the inoculations as a cure to cervical cancer — would have a much greater effect on cervical cancer rates by mandating its use later.
Cervical cancer rates are less than one per 100,000 women until age 20 and then begin to pick up in the late 20s and early 30s. Thus, women who likely contracted HPV in their early 20s could be protected by Gardasil taken at 17 or 18.
GlaxoSmithKline is developing another HPV vaccine, Cervarix, which has not been licensed but is expected to be released later this year. It is effective for 4 years, according to an April 2006 study in Lancet, a British medical journal.
Risk vs. reward
Dr. Mona Saraiya, a medical epidemiologist in the Division of Cancer Prevention and Control at the CDC, says nearly all sexually active woman are exposed to HPV.
“However, only a few will get an infection that stays and won’t go away, and only a portion of those will get a precancerous lesion. At that point, only a few will eventually develop cervical cancer,” Dr. Saraiya said.
Fewer than one-hundredth of 1 percent of the 108 million U.S. women older than 18 (0.009 percent) get cervical cancer and even fewer die from it. There were an estimated 9,700 new cervical cancer cases and 3,700 fatalities in 2006, according to the American Cancer Society.
But the fact that very few U.S. women are affected by cervical cancer, statistically speaking, hasn’t stopped the rush by lawmakers to push mandatory HPV vaccines for school girls.
Earlier this month, Texas became the first state to enact an HPV vaccine law when Gov. Rick Perry bypassed the Legislature and signed an executive order mandating all girls entering sixth grade be inoculated. Mr. Perry drew fire when it was revealed that his former chief of staff was lobbying for Merck. Lawmakers are trying to reverse the order.
In Maryland, HPV legislation was pulled days after a Baltimore Sun report on Merck’s lobbying efforts in Annapolis. The bill’s sponsor, state Sen. Delores Kelley, Baltimore County Democrat, cited the growing burden on families because of the high costs of mandatory vaccinations.
Virginia Delegate Phillip A. Hamilton, Newport News Republican, sponsored the HPV-vaccination legislation that his state’s House passed earlier this month and is expected to become law.
“What was intriguing to me was that it was a cancer vaccine,” he said.
Mr. Hamilton, who has received contributions from Merck in the past, said the pharmaceutical company played no role in his decision to the sponsor the bill.
“It was a positive step. It was about preventing cancer, nothing else,” Mr. Hamilton said.
D.C. officials have just begun hearings on a proposal to require HPV vaccinations before girls turn 13 and to create an HPV reporting program in the city’s Department of Health.
Merck has waged an extensive lobbying campaign in statehouses, and has helped raise the profile of HPV through a large-scale communications campaign, highlighted by the “Tell Someone” TV ad being shown on channels with high-teen viewership, such as MTV.
Wall Street analysts predict that Gardasil, which is projected to generate $2 billion to $4 billion this year without state mandates, will help offset losses Merck endured after it pulled Vioxx off the market in 2004.
Vioxx, an FDA-approved anti-inflammatory drug for osteoarthritis and acute pain that was used by 2 million people, was linked to increased risk of heart attack and stroke.
“Merck’s goal is to support efforts to implement policies that ensure that Gardasil is used to achieve what it was designed to do: help reduce the burden of cervical cancer — the second-leading cancer among women around the world — and other HPV-related diseases for as many people as possible, and as quickly as possible,” Merck said about its lobbying efforts.
Fast track vs. family values
Merck’s lobbying efforts and the legislative push for mandatory HPV vaccinations have attracted the attention of pro-family groups such as Focus on the Family, which supports HPV vaccinations but says they should not be mandatory. Other conservative groups such as the Family Research Council say requiring HPV inoculations is tantamount to endorsing premarital sex.
“Because HPV infection is caused by sexual activity, it is not transmitted by casual contact and therefore is not in the same class as other diseases like polio for which mandatory, school-based vaccination is a public-health imperative,” Family Research Council President Tony Perkins said in an alert sent to its members to lobby Mr. Perry to rescind his Texas order.
Delegate John J. Welch III, Virginia Beach Republican, opposes his state’s measure for several reasons.
“I think parental rights are paramount. They should trump everything,” Mr. Welch said.
“When we have a drug that can cure cancer, of course I’m all for it,” he said. “But given the fact the drug is so new, I don’t think that the commonwealth should mandate it.”
Once a major killer in the U.S., cervical cancer has been nearly wiped out since the creation of the Pap test, which detects precancerous lesions and early cancer and is credited with a 74 percent drop in cervical cancer deaths since 1955.
The CDC says most cervical cancer diagnoses in the U.S. are in women who either have never had a Pap test or have not had a Pap test in the previous five years. Those inoculated with Gardasil still will have to have regular Pap tests for the disease, which is hard to detect because it does not usually cause pain.
Cervical cancer does have high mortality rates in low-income regions of U.S. and poor nations where health care coverage is not routine. Cervical cancer is the fifth most common cancer among women worldwide, according to the World Health Organization, and kills about 230,000 women a year, most in developing countries. Because of these figures, public health officials still back use of the vaccine.
“The vaccine is not nearly as effective as vaccines for mumps or measles, but it is an important step forward in public health,” said Dr. John Swartzberg, director of public health policy at the University of California at Berkeley. “The vaccine will decrease the two most common strains of HPV that cause cancer, and we’ll be left with strains that have far less potential to cause cancer. In this case, the benefits outweigh the risks.”
What we don’t know
As with any new drug, there are potential risks that short-term studies used for federal approval don’t detect.
Dr. Clayton Young, an obstetrician-gynecologist in Texas, is concerned that Gardasil will actually strengthen cancer-causing strains of HPV.
“My concern is that we are pushing ourselves into something worse than we already have,” Dr. Young said. “Vaccinating for only two strains may lead to an increase in infection with other and possibly more aggressive strains.”
Gardasil is effective against two of 10 carcinogenic HPV strains. Those two strains dominate the current statistics, estimated to have caused 6,800 new cervical cancer cases in 2006, while the other eight strains combined affected 2,900 women.
The probability of additional cancer-causing HPV strains leading to as many cervical cancer cases as today is minute, said Dr. Haupt, executive director of medical affairs in Merck’s vaccine division.
Despite Merck’s doubt, the company is studying the additional cancer-causing HPV types in Scandinavian countries, where national cancer registries allow drug companies to track people with the disease.
“It is an important issue to us,” Dr. Haupt said. “But we think the two types of HPV that Gardasil work for are unique, and if other types become more common, they will not cause cancer at the same rate and won’t over time.”
Physicians also point to concerns about Gardasil that cast doubt on the vaccine’s overall capability to stop cervical cancer from occurring in females. For instance, clinical trials for the vaccine’s effectiveness at preventing cervical cancer did not include the age group of girls for whom the vaccine is being recommended by federal regulators.
“The number one problem with the vaccine is that it has not been tested adequately on the group that is recommended to get it,” said Dr. Joseph DeSoto, a fellow in the American Institute of Chemists and a physician-scientist at the National Institutes of Health.
According to Merck’s clinical study documents on Gardasil, 20,541 women ages 16 to 26 participated in four studies. The documents show some data is available on 9-year-old girls related to immune responses to the vaccine but not whether it prevents cancer.
Because most 9-year-old girls are not sexually active, it is not possible to test the effectiveness of Gardasil against cervical cancer, Mr. Haupt said. Instead, the clinical trials measured antibody responses against HPV as a proxy for cervical cancer.
Merck conducted two clinical trials that involved 1,121 girls ages 9 to 15, according to Merck’s labeling documents for Gardasil.
“The clinical trials tested younger girls, but they only looked at immune response to the vaccine, not whether it prevented cervical cancer,” Dr. Young said. “It has not been studied long enough to know that it prevents cervical cancer.”
Jim McElhatton contributed to this report.
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