Human papillomavirus (HPV) is a critical factor in the development of cervical cancer and can lead to genital warts and other clinical sequelae. Two vaccines against HPV have been developed recently that have shown to be safe and effective. The use of HPV vaccines holds promise for alleviating the burden of illness related to HPV infection. However, barriers specific to HPV vaccines, as well as barriers related to adolescent vaccination in general, may pose challenges to widespread implementation. Among these are: (1) lack of knowledge among the US population about HPV transmission and its relation to cervical cancer and other anogenital diseases; (2) parental concerns about vaccines in general and about vaccinating minors against sexually transmitted diseases; (3) financing by the government and private insurers for newly recommended vaccines; (4) challenges related to adolescents' healthcare-seeking behavior and health insurance coverage; and (5) barriers related to the dynamics of HPV infection (eg, protection against only certain types of HPV, duration of immunity, immunization schedules). Addressing these concerns will be critical in effective implementation of HPV vaccines and, potentially, vaccines, against other sexually transmitted diseases.
(Am J Manag Care. 2006;12:S484-S491)
Vaccines are among the most cost-effective interventions in healthcare, but economic factors may interfere with their optimal delivery and utilization. This may be particularly true for vaccines against human papillomavirus (HPV), which have several unique characteristics that set them apart from other vaccines. This article discusses potential barriers to HPV vaccination related to public perceptions, vaccine economics, practice infrastructure, and the dynamics of HPV infection. To be successful, HPV vaccination efforts must address the concerns of healthcare providers, parents, and adolescent patients involved in the decision to be vaccinated against HPV.
Challenges to HPV Vaccination
It is now widely accepted that infection with HPV is a necessary, although not sufficient, etiologic agent in the development of virtually all cases of cervical cancer.1 HPV infection can also lead to other significant clinical sequelae, including genital warts, precancerous cervical dysplasia, laryngeal papillomatosis, other anogenital cancers, and possibly some head and neck cancers.2
Two HPV vaccines have recently been developed and shown in large-scale clinical trials to be immunogenic, safe, and highly effective in preventing cervical dysplasia and (for 1 of the vaccines) genital warts.3-8 One of these vaccines was recently licensed by the US Food and Drug Administration for use in adolescent and young adult women,9 and approval may be expanded in the future to include males and older adults, as additional clinical trial data become available. If widely utilized, these vaccines could have a substantial impact on reducing the burden of HPV-associated illnesses within the population. However, barriers specific to HPV vaccines, as well as barriers related to adolescent vaccination in general, may pose challenges to their implementation.
Perceptions of HPV Infection
Studies consistently demonstrate that the US population generally has little awareness or knowledge of HPV, and that there is a pervasive lack of understanding that HPV is sexually transmitted, or that HPV infection is linked to anogenital diseases like cervical cancer or genital warts.10-15 For example, in a study of 321 college students, only one third had ever heard of HPV, only 17% correctly indicated that HPV was sexually transmitted, and only 2% identified HPV infection as a risk factor for cervical cancer.11 Similar results have been found among adolescent and adult populations.10,12,13
The general lack of knowledge about HPV may explain why the risk of acquiring HPV infection, or of developing HPV-related disease, is commonly underestimated, both at the individual and societal levels.11 Such a low perception of risk is likely to impair community demand for HPV vaccination. As a consequence, significant and sustained public educational efforts designed to raise awareness about HPV and the benefits of HPV immunization will be necessary to ensure that these vaccines are widely utilized. Public education may be especially important if policies promoting HPV vaccination in males are adopted in the future, because the degree of clinical benefits afforded to males by HPV vaccination is likely to be less than that of females. Focusing additional attention on the indirect benefits provided to women by widespread HPV vaccination of men ("herd immunity") may be useful for promoting the use of these vaccines among both sexes.
The perceptions of parents about HPV vaccines will also be critical to HPV vaccination success, because parental consent will be required to administer HPV vaccines to minor children. Significant lay media attention has focused on the possibility that the sexual nature of HPV transmission may significantly hinder parental acceptance of these vaccines, which could, in turn, lead to their underutilization. For example, one oftcited concern is that parental consent to HPV vaccination may be misconstrued by adolescent children as condoning early sexual activity. Another is that parents (or physicians) will find it insurmountably difficult to explain to young adolescent children the need for vaccination against a sexually transmitted infection (STI).
Despite the extensive media attention given to these types of concerns, research on parental attitudes about vaccines actually suggests that opposition to vaccination against STIs in general, or to HPV vaccination in particular, is not widespread.16-22 Studies indicate that the majority of parents favor HPV vaccination, with 65% to 84% indicating that they would want their child immunized against HPV if the vaccine were available.16,17,20 Furthermore, in a qualitative study that explored in depth the parental attitudes about vaccination against STIs, including HPV, the perception that their children were at low risk for contracting the infection or a lack of understanding that vaccination is most beneficial if performed before the onset of sexual activity were found as the primary reasons for rejecting vaccination, as opposed to concerns about promoting sexual activity.18 Moreover, in another study that evaluated the relative contribution of 4 different vaccine characteristics on parental vaccine acceptability—disease transmissibility (STI vs non-STI), severity of infection prevented by vaccination, vaccine efficacy, and availability of behavioral methods to prevent infection—there was little difference between STI and non-STI vaccines.19 Factors such as disease severity and vaccine efficacy were comparatively much more influential for parents.
Taken together, these results suggest that the sexual transmissibility of HPV may not be a significant barrier to parental consent for HPV vaccination for their children, and indicate that educational efforts may be better directed toward other issues, such as describing vaccine efficacy or the high prevalence of HPV infection among adolescents.
In addition, the concerns of other groups with interest in adolescent health, such as teachers, schools, and religious organizations, will also need to be addressed. In addition to concerns related specifically to HPV vaccines, misperceptions about the safety of vaccination in general may pose additional barriers to the use of these vaccines. For example, although serious adverse events related to vaccination are exceedingly rare,23 they garner a disproportionately high level of media attention, leading many parents and patients to be suspicious of new vaccines that do not yet have a long-standing track record of safety.24 A litany of other misperceptions about vaccine safety add to the fear of vaccination, such as concerns that administering too many vaccines during childhood can "overwhelm the system," leading to a weakened immune state25,26; that vaccines may actually cause the disease they are designed to prevent27; or that vaccination may cause other health problems, such as autism or allergies.27,28 The large number of studies that allay these concerns may not be enough to substantially impact public opinion about the safety of vaccination.29-31
Vaccine Financing for Adolescents
As the number of recommended childhood and adolescent vaccines increases and vaccines become increasingly expensive,32,33 financing for newly recommended vaccines grows as a potential barrier. At an announced retail price of $120 per dose ($360 per series) for the quadrivalent HPV vaccine,34 the adolescent HPV vaccination series will be the most expensive series ever universally recommended by the Advisory Committee on Immunization Practice (ACIP) of the Centers for Disease Control and Prevention.
In the private insurance market, parents and their adolescents will face the question of whether their plans cover all or part of the vaccine cost. Other costly vaccines that have recently been recommended (such as the pneumococcal conjugate vaccine, which was the most expensive vaccine series ever universally recommended at its introduction in spring 2000) have been covered by most, but not all, private health plans within a year of their recommendation by ACIP.35
Lack of health plan coverage leaves parents with a variety of options for their children: (1) pay out of pocket for the vaccine series; (2) appeal to their health plan medical director and hope that the appeal succeeds and coverage for a vaccine is approved as a benefit; (3) wait to vaccinate, in hopes that the health plan will approve coverage in the future; (4) seek financing for the vaccines through public programs financed at the federal or state level. These options will be discussed further below.
Of note, a recent national study found that 4 of every 5 parents would, if given the opportunity, pay a modest amount ($3-$6) more per month in family health plan premiums to guarantee that their private health plans would cover all new vaccines recommended by ACIP.36 From an actuarial perspective, $6 more per month greatly exceeds the increase in premiums that would result if a health plan decided to cover HPV vaccine for its eligible population. Healthcare providers can advise parents who want HPV coverage for their adolescents to lobby their employers and plan benefits boards for such coverage. Such appeals from plan enrollees may be more effective than appeals from healthcare providers themselves.