The HPV Vaccine: Deciding for Our Children

Family North Carolina Magazine—May/June 2007

by Joseph. R. Zanga, MD, FAAP, FCP 

For as long as many of us can remember, a driving force and Holy Grail of medical research has been to find a cure for cancer. Embedded in this work, but often less publicly noted, was the hope of primary cancer prevention. So while many tinkered with diet and environmental modifications (vitamins, airborne toxin elimination, smoking cessation, etc.) medical researchers were hard at work developing vaccines which would make each individual as safe from cancer as they were from measles, chickenpox, and whooping cough (pertussis). The announcement that this had finally occurred, that a vaccine to prevent a particular cancer was now available, was enthusiastically heralded by the pharmaceutical industry, health professionals, government, and the general population alike. Unfortunately, science is not press-releases and “the devil is often in the details.” So, let’s examine the new vaccine directed to prevent Human Papilloma Virus infection and dissect some of the details.

What is HPV?
Human Papilloma Virus (HPV) is an almost exclusively sexually transmitted infectious agent with four subtypes specifically known to frequently cause clinically significant disease. Two of the HPV infections (types 6 and 11) cause distressing wart-like growths in the genital area where skin-to-skin contact takes place during sexual activity. These subtypes can also cause some changes in the cells of the cervix, but are not known to cause cervical cancer as do two other subtypes.

Make no mistake, this is a very pervasive infection which may not be possible to prevent by the conscientious use of condoms. More problematic is the fact that while two high risk strains (types 16 and 18) account for the majority of cervical cancers, at least 13 of the almost 40 strains of HPV known to infect the genital tract, can also cause cancer, though less frequently.^{(1, 2)}

Fortunately, even infection with one or both of the two high-risk strains does not always result in cervical cancer. While HPV may be the most common sexually transmitted infection in the United States, we know that 90% of these infections clear on their own after a year or two.⁽³⁾ We also know that while the high-risk strains cause 70% of cervical cancers, their occurrence in a nationally representative sample of women aged 14 through 59 was, at any one time, 1.5% for HPV-16 and 0.8% for HPV-18.⁽³⁾ Also, in the US, for reasons yet unknown, the incidence of both infection and cervical cancer appear to be declining. That said, it is still the 11^th most common cancer in American women, and takes the lives of over 3,500 women annually.⁽⁴⁾ However, this number reflects a 70% decrease in cervical cancer deaths since screening for this disease became common in the middle of the last century.⁽⁴⁾

The Vaccine
Unfortunately, women still do die of this disease. Unfortunately, for a variety of financial and social reasons, not all women are regularly screened for cervical cancer and not all of them who are follow up with appropriate treatment. This is not an uncommon occurrence for a number of diseases, some lethal, some not, which people tolerate or ignore until treatment is difficult or impossible. HPV infection is also difficult to avoid unless one remains abstinent throughout life or, having been abstinent, marries an uninfected man and thereafter remains monogamous. Since none of this can be guaranteed, a vaccine which prevents infection with little or no personal effort sounds very attractive. Some see it as simply another part of our efforts to protect the “public health.” Unfortunately, the standard dictums relating to preserving public health do not clearly pertain in this case.

In June of last year, the first vaccine with demonstrated ability to prevent cancer, in this case cervical cancer caused by HPV, was licensed for girls and women starting at age nine. The manufacturer promoted it heavily, directly to the public and to groups and organizations dedicated to prevention and cure of cancer and preservation of public health. Support for this vaccine was immediate. The Governor of Texas was so impressed that he bypassed the legislative process and mandated the vaccine for all girls at 6^th grade entrance. Subsequently, the Texas Legislature has begun a process to rescind the Governor’s order, while several other states are considering mandates. In almost all instances vaccination is being promoted as a logical prevention measure and as a simple addition to the list of vaccines already required for school attendance. The mantra of eliminating at least one kind of cancer is so powerful that many are ignoring an important fact which might bring this discussion to a more logical conclusion.

The first and most obvious is that HPV is a sexually acquired infection. Unlike measles, chickenpox, and whooping cough, it cannot be acquired by sitting next to an infected person in a classroom. Only by having genital intercourse can this virus be transmitted, an unlikely event in most classrooms.

While it is true that a not insignificant number of our adolescent population is genitally sexually active, that number, thanks to abstinence education and promotion, is in a multi-year decline. Critically, the highest incidence of HPV infection occurs within the first few years of beginning sexual activity, but even more critically, as noted earlier, approximately 90% of the infections clear on their own within two years.

Still, immunized individuals will be protected from the virus which causes most of the declining numbers of cervical cancers – provided, of course, immunity persists throughout all of the individual’s sexually active years. At this time, we know that the existing vaccine maintains protection for approximately 5 years. ⁽⁵⁾ Speculation is that it will be longer lasting, but the history of other vaccines makes most physicians less confident. For example, measles vaccine was heralded because it would prevent a disabling and potentially devastating disease. It was also suggested that immunity, just as immunity acquired from natural infection, would be life-long.

Vaccine Troubles
We learned years later, after several localized epidemics, that vaccine immunity waned and that booster doses would be required. We’ve learned the same about the chickenpox vaccine, and in perhaps a harbinger of things to come, the most recent of the whooping cough vaccines, which was once required to be given only until age five, now requires booster doses for adolescents and the same is recommended for all adults. It is likely then, that those immunized with the current HPV vaccine will need additional doses throughout their sexually active lives. Experience with even the three aforementioned vaccines tells us that convincing the public to re-immunize is an extraordinarily difficult task. Girls immunized at the earliest possible age (the suggested 11-12 years of age) would seem to be at risk just at the time when the majority will begin to be sexually active. (The American College of Pediatricians has recommended that HPV vaccine registries be developed to track immunized women so that they can be informed about waning immunity).

Adding to this, we know that no vaccine is perfect. We know specifically that women are unprotected by the existing HPV vaccine from other HPV strains which cause 30% of cervical cancers because those strains are not contained in the current vaccines. For this reason, it remains a strong recommendation that even, perhaps especially, vaccinated women continue to have yearly cervical cancer screening (Pap test). Many physicians are justifiably concerned that the false sense of security engendered by the HPV vaccine, when given to young girls who may not fully comprehend all of the cautions, will cause even more women to neglect this critical element of comprehensive preventive medical care.

Is it Safe?
As with any new product, questions of safety are always raised. With respect to women over the age of 16, the vaccine does appear to be safe, with only minor and localized side effects. This conclusion is based on tests of over 20,000 women 16-26 years of age. However, we should be cautious in drawing the same conclusion for females younger than 16, as the vaccine was not tested in a similar number of girls between 9 and 15 years of age. The expectation is that we will learn about the safety of the vaccine from what is termed “post-marketing” experience. In the past, other drugs used for children, but not tested for their safety in this population, were called, “uncontrolled/unregulated experimentation” on our children. The pediatric community, in particular, has petitioned Congress and the FDA to reduce the occurrence of this dangerous practice.

Testing, of course, is expensive and if it were thoroughly carried out would undoubtedly raise the HPV vaccine’s cost beyond what it is at present. As with some other vaccines, one injection does not provide protection. Three doses are required to achieve the current predicted level of protection, given at two month intervals. The immunizations are paid for by most public and private insurers, so that while the cost to the individual may be low or absent, the cost to society will be great. Each dose is sold directly by the manufacturer for approximately $120. Regardless of whether the immunization is given in a primary care physician’s office, in a public health department, community clinic, or even in school, there are additional costs beyond the manufacturer’s price. A $150 to $200 charge for the vaccine and its administration is the current range, which takes into account the cost of vaccine purchase and storage, personnel costs, equipment costs (needles, syringes, etc.), and facility overhead costs. Legislative mandates for a vaccine often require a government payment for the vaccine and its administration, a cost which might burden already over-extended state budgets.

Finally, as noted earlier, this is a unique disease and unique vaccine. Acquisition of HPV can only take place in the context of sexual intercourse. Here we have then a most perfect opportunity for parents, deciding on the timing of vaccine initiation, to sit with their children to discuss the importance of abstinence, and for churches, schools and health professionals to do likewise. For most families and their children, even for those who have instilled a respect for the idea that sexual intercourse and most other sexual activity is reserved for marriage, the timing of this discussion will be different.

Role of the State
The state’s role in this discussion should be to facilitate that conversation and not to preempt it. Unlike the situation with other vaccines, this is a private rather than a public health issue.

Given that this vaccine will prevent no more than 70% of an already declining number of cervical cancers, given that we are unsure of the duration of protection, given that regular screening for cervical cancer is still critically important, given that this is the most expensive vaccine yet marketed in this country, and given that we should not ignore the opportunity that this vaccine presents to have parents and others discuss issues of sexuality with our children, what do I recommend to my patients? I recommend that when they make the decision that they will likely soon be sexually active, preferably deciding to be abstinent until marriage, that at that time they begin the vaccine series. Guiding them to that decision is part of the life-long responsibility of their parents, churches, schools, and health professionals. I applaud the development and use of the HPV vaccine, but look forward to that use being driven by science and not mass marketing.

Joseph Zanga is the president of the American College of Pediatricians, and he is professor of pediatrics, Brody School of Medicine at ECU.

Endnotes

[1] Gravitt PE, Jamshidi R. Diagnosis and management of oncogenic cervical human papillomavirus infection. Infectious Disease Clinics of North America. 2005; 19(2).

[2] Villa LL, Costa RL, Petta CA, et al. Prophylactic quadrivalent human paillomavirus (types 6, 11, 16, and 18) L1 virus-like particle vaccine in young women: A randomized double-blind placebo-controlled multicentre phase II efficacy trial. The Lancet Oncology. 2005; 6(5).

[3] Dunn EF, Unger ER, Sternberg M, et al. Prevalence of HPV infection among females in the United States. JAMA. 2007; 297(8):813-819.

[4] Weisberg S, Castellan D. Human papilloma virus vaccination. Amer Coll Peds Website: http://www.acpeds.org/?context=art&cat=10006&art=140biskit=238560372. Accessed 3/13/2007.

[5] Villa LL, Costa RL, Petta CA, et al. High sustained efficacy of a prophalactic quadrivalent human papillomavirus types 6/11/16/18 L1 virus-like particle vaccine through 5 years of follow-up. Br J Cancer. 2006; 95(11):1459-1466.

Copyright © 2007. North Carolina Family Policy Council. All rights reserved.