Saturday, July 26, 2008
Serious neurologic, thromboembolic, and autoimmune complications have been reported in patients who received human papillomavirus vaccines.
By Allison Gandey
July 26, 2008 Serious neurologic, thromboembolic, and autoimmune complications have been reported in patients who received human papillomavirus (HPV) vaccines. Although not the norm, experts suggest that the events are grave enough to encourage caution. "The side effects that have been reported are real and they cannot be brushed aside," Diane Harper, MD, from the Dartmouth Medical School, in Hanover, New Hampshire, told Medscape Oncology. Dr. Harper was a principal investigator of clinical HPV vaccine trials for both Merck and GlaxoSmithKline.
News reports of adverse events, teen paralysis, and death have fueled public concern. Back-to-school immunization clinics are stocking up on Merck's Gardasil and more than16 million doses have reportedly already been distributed in the United States alone. But many parents are questioning whether their children should be vaccinated. And many women are wondering whether they should be vaccinated too.
According to the US Food and Drug Administration (FDA), as of June 30, 2008, more than 9700 adverse events have been reported since the vaccine was approved 2 years ago. Of these, 94% were classified as nonserious events and 6% as severe.
Serious Adverse Events
Most Commonly Reported Events
To prevent fainting, which can sometimes cause serious harm and lead to head injuries, Dr. Harper recommends that patients receive vaccines on a full stomach and be seated when the shots are administered. The FDA recommends that patients remain seated for up to 15 minutes after vaccination.
Dr. Harper also suggests that physicians not vaccinate patients with personal or family histories of the more serious conditions outlined in recent adverse-event reports. "Physicians have a responsibility to communicate risks to patients and if patients and families are concerned, it is reasonable to hold off on vaccinating," Dr. Harper said.
It is a sentiment that is echoed by others, such as Abby Lippman, PhD, from McGill University, in Montreal, Quebec, who is chair of the policy committee at the Canadian Women's Health Network. In this month's issue of the Journal of Epidemiology and Community Health, she expresses concern about public policies that have seemingly rushed to embrace HPV vaccination. "Why the hurry," Dr. Lippman asks. Especially in developed countries where there is no epidemic of infection and mortality rates from cervical cancer have been in decline.
What is Causing Adverse Events?
The cause of recent complications remains a mystery and it is difficult to know whether they are linked to vaccines. "Nobody knows why we are seeing adverse events," Dr. Harper said.
Members of the antivaccine movement point to a number of potential perils, including the presence of aluminum in injections. Like many vaccines, Gardasil contains aluminum salts. Each 0.5-mL dose contains approximately 225 μg of aluminum, 9.56 mg of sodium chloride, 0.78 mg of L-histidine, 50 μcg of polysorbate 80, 35 μg of sodium borate, and water.
"The scientific work to date seems to suggest that aluminum salts in vaccines are safe," Dr. Harper said. But she told Medscape Oncology that she heard that 1 lot of Gardasil might have had an accidentally high yeast concentration, and this might be why there are problems. "No one knows for sure," Dr. Harper said.
The manufacturer was not available to comment about product yeast concentrations, but directed Medscape Oncology to an online statement responding to questions about recent adverse effects. "Merck has analyzed the adverse events reported for Gardasil relating to the recent reports of death and paralysis, and based on the data available to Merck, believes that no safety issue related to the vaccine has been identified. These types of events are events that could also be seen in the general population."
Richard Haupt, MD, executive director of clinical research at Merck's research laboratories added: "We remain confident in the safety profile of Gardasil."
FDA and CDC Issue Joint Statement Reassuring Clinicians and Patients
Responding to public concern, the FDA and the Centers for Disease Control and Prevention (CDC) issued a joint statement on Tuesday reassuring clinicians and patients about the safety of Gardasil. A second vaccine, GlaxoSmithKline's Cervarix, is already available in some countries, but is still being assessed by the FDA.
Despite company and regulatory assurances, some clinicians, who are also parents, say they are less confident about the safety of the vaccines. After reviewing the information, Scott Ratner, MD, a cardiologist with a practice in Franklin Square, New York, and his wife, a rheumatologist, opted to have their 17-year-old daughter vaccinated. It is a decision they say they now regret.
Following vaccination, their teenage daughter began showing signs and symptoms of autoimmune disease. "She went from being a healthy, active teen running, playing lacrosse, and participating on swim team to becoming a chronically ill patient," Dr. Ratner said.
"I worry about the kids who may be having problems, are perhaps struggling with immune damage, and are feeling generally achy and unwell, but are probably going unreported and undiagnosed," he said. Dr. Ratner has 2 younger daughters and he says he definitely won't be encouraging either of them to be vaccinated.
Gynecologist Christiane Northrup, MD, told Medscape Oncology that she won't be advocating that her daughters be vaccinated either. Dr. Northrup appeared on a recent episode of the Oprah Winfrey Show, which has an estimated 20 million viewers per week, most of them women. She told viewers that healthcare dollars would be better invested elsewhere.
Questioning the Safety
Dr. Northrup recommended that the money going toward vaccines and related programs be allocated to general health and wellness initiatives and proper nutrition. This harkens back to the age-old debate between Louis Pasteur and Antoine Beauchamp, Dr. Northrup suggests.
For most of his career, Pasteur subscribed to germ theory, while Beauchamp backed the more unpopular theory of biological terrain. The question: Is it the germs themselves that make people sick or a weakened state of immunity that allows germs to take root? "Pasteur was widely supported, but on his death bed conceded that Beauchamp was right," Dr. Northrup said during an interview. She suggests that this is what experts should be concentrating on now.
Instead of focusing on germ theory by pouring efforts into HPV vaccines, she says more resources should be dedicated to fostering the overall health of the host.
Dr. Lippman makes a similar argument and points to the capacity of healthy, immunocompetent women to spontaneously clear up to 90% of HPV infections infections, she says, almost everyone will one day acquire within 1 to 2 years.
When Gardasil was approved in the United States in June 2006, it was hailed as an important day for public health and for women's health. Dr. Harper was quoted as saying that the vaccine is the biggest advance since the Pap smear. Dr. Harper told Medscape Oncology that she still thinks this is the case, but enthusiasm must be tempered with caution.
Dr. Harper noted that we shouldn't be calling the new immunizations cervical cancer vaccines. "Even if everyone was vaccinated, we would still have cervical cancer," she said. "I don't want people to be lulled into thinking this will prevent cancer. If Pap screening rates decline, cervical cancer rates will rise," she emphasized.
If Pap Screening Rates Decline, Cervical Cancer Rates Will Rise
The decline in cervical cancer in developed countries has been largely attributed to regular Pap screening something Dr. Harper believes has done a superb job. Women who haven't received an HPV vaccine, and even those who have, are still encouraged to undergo regular screening.
At the 2006 American Society of Clinical Oncology annual meeting, delegates were enthusiastic. One presenter showed a series of cervical cancer photos and told observers that "these types of pictures will soon disappear in clinical oncology."
Unfortunately, that utopian prediction is unlikely. "Cervical cancer is not a vaccine-preventable disease," Dr. Lippman said during an interview. And in her recent editorial, she points out that surrogate end points not cervical cancer were used to measure the efficacy in the clinical trials.
"No one would want to wait to see cervical cancer develop in participants," she writes. "But the general failure to mention that the precancerous lesions chosen for study are not only potentially removable, most (those that are CIN 2) would probably have resolved on their own without any intervention, is arguable."
Many Questions Remain
As previously reported by Medscape Oncology, Sharmila Makhija, MD, from the University of Alabama School of Medicine, in Birmingham, pointed to other limitations of HPV vaccines. Dr. Makhija is the principal investigator on Merck's FUTURE III trial, looking at the vaccine's efficacy in women 24 to 45 years old, and is a coinvestigator on GlaxoSmithKline's vaccine trials.
Dr. Makhija noted that the bulk of the work to date has focused on just 2 types of HPV 16 and 18. She added that, going forward, more virulent cancer-causing strains could emerge, making it difficult to eliminate disease. And other important questions remain:
"While vaccine proponents emphasize the many thousands of women who participated in clinical trials of the product, they gloss over how few young girls in the 9 to 13 year age range, targeted specifically for school-based immunizations, were included," Dr. Lippman argues. She said that only the very short-term immunogenicity and safety, and not the efficacy, of Gardasil was studied.
"It is a good vaccine," Dr. Harper said. "We are simply still in the early stages of investigation."
The World Health Organization (WHO) has weighed in on the vaccines and is recommending that they be considered only 1 component of any successful strategy. Immunization will have to be added to the other aspects of cervical cancer control, Andreas Ullrich, MD, medical officer at WHO's department of chronic diseases and health promotion, said in a news release. "There is no question that early detection will continue to be a key element."
Merck is encouraging healthcare providers and consumers to report any adverse events associated with Gardasil to the company and to the US Vaccine Adverse Event Reporting System at 1-800-822-7967.
J Epidemiol Community Health. 2008;62:570-571.