Addressing the Declining Rates of Completion and Gender Coverage Inequity in Human Papillomavirus Vaccination in the United States

Human papillomavirus (HPV) is a significant contributor to the cancer burden in the United States. More than 21 000 cases of cancer are attributed annually to the virus. Although the vaccine has been shown to be both safe and effective, it remains underutilized, particularly among males. Spencer et al. (p. 946), in this issue of AJPH, address the very important question of what helps predict, in boys and girls, why the recommended HPV three-shot series is initiated but not completed, which results in suboptimal protection against HPV infection and related complications.

Using claims data, Spencer et al. determined the rate of three-dose completion within 12 months of taking the first dose. They showed that the vaccine uptake rate of three doses within 12 months is still well below the 80% threshold for Healthy People 2020 and has declined since recommendations for full female and male vaccination were promulgated. Their work is important for several reasons. First, they used claims data that are increasingly important in the analysis of health services delivery and medical care evaluation.¹ As the electronic health record is more integrated into the American health care system (and ideally links to vaccine registries), it becomes a valuable source of information for the public health community. The incidental finding that about 60% of possible study participants were excluded because they were not continuously enrolled in the same health plan for 24 months highlights the value of such studies and merits additional inquiry. Second, the results of the work by Spencer et al. remind us that despite an abundance of guidance about setting up systems for administering all vaccines, we must be vigilant about implementing those systems and continuously demonstrating their value in increasing universal vaccine uptake.

ORIGINS OF HPV VACCINE

HPV vaccine was first licensed by the Food and Drug Administration in 2006.² This quadrivalent vaccine was created to prevent cervical cancer. Hence, the initial research, evaluation, and regulatory and marketing efforts focused primarily on females. This focus had the unintended adverse consequence of delaying an HPV vaccine recommendation for males until 2011. During the seven years since that recommendation was made, there has been a continued delay in uptake of the vaccine among males to allow parity with females.³ The implications of this are a lack of equity that puts males and, therefore females, at increased risk for disease, and an underappreciation of the benefits of the vaccine to all adolescents.

HPV-ASSOCIATED CANCERS

The “epidemic” of HPV-associated head and neck cancers, mostly in men younger than those with these cancers previously, and anogenital cancers in males and females merits increased attention. Oropharyngeal cancers could be on track to surpass cervical cancer by 2020.⁴ This alarming increase in HPV-associated oropharyngeal cancer highlights the importance of enhanced efforts to increase vaccination among young men. These oropharyngeal cancers have markedly increased survival compared with oropharyngeal cancers associated with other risk factors.⁴

MALES AS ASYMPTOMATIC HPV RESERVOIRS

The low three-dose HPV uptake rate demonstrated by Spencer et al. has significant implications for the persistence of a reservoir of asymptomatic infected males.⁵ A nationally representative sample demonstrated that overall genital HPV infection prevalence for men aged 18 to 59 years was more than 45%. A bimodal pattern of genital HPV infection showed peaks of infection among men aged 20 to 32 years and a second, narrow peak among men aged 58 to 59 years. HPV genotyping identified high-risk and low-risk HPV. HPV types, oncogenic and nononcogenic, were broadly represented among the study participants. This “reservoir” of HPV in men of all ages and the possibility of continuous transmission are clear concerns. The opportunity to continue evaluation of HPV vaccine in a broader range of male age groups could provide the data needed to reevaluate the current approved ages for HPV vaccine use in the United States. Other countries recommend HPV vaccine use in older male age groups.⁶ Despite the potential need for broader age group vaccination, younger adolescents should remain a priority population because of their enhanced immunologic benefit, which persists into adulthood, from the HPV vaccine.

Vaccination of males and eradication of the disease reservoir is one more way to protect all partners from HPV transmission during any sexual behavior. It is very safe to say that if all males were immunized against HPV, substantial benefit would accrue to all sexually active people. Researching, marketing, recommending, and administering HPV vaccine as a vaccine of equal benefit for all adolescents and young adults will also help destigmatize the vaccine and promote uptake.

VACCINE HESITANCY

Another opportunity highlighted by Spencer et al. is the importance of timely follow-through to ensure multidose vaccine uptake. Work by Kornides et al.⁷ describes strategies for increasing uptake even when the vaccine was initially refused. This work demonstrated that on a subsequent visit to the clinician, there was a 45% secondary uptake and an additional 24% of parents intending to vaccinate within 12 months. Results of parent surveys highlighted increased effectiveness when the clinician was engaged, objective, and nonjudgmental at the time of first vaccine declination. The work of Spencer et al. reconfirms the fact that receipt of an additional vaccine (influenza) is associated with HPV vaccination. This would imply that many people are vaccine receptive and willing to be vaccinated when the underlying logistical, clinical support, educational, and psychological requirements of the family are met. Vaccine hesitancy can be overcome with caring, honesty, and empathy.

CONCLUSIONS

Spencer et al. define well many complex variables that can be addressed in concert to create effective vaccination programs and the compelling need for these programs. The clinical and public health communities must emphasize the increased immunologic and clinical benefits, which persist into adulthood, of receiving the HPV vaccine as recommended. Many of the health benefits unavailable to females and males caused by shortcomings in vaccinating young females and young males could be overcome with an equal emphasis on vaccinating all adolescents using the best systems possible, the same messaging, and the same provider confidence in the need for and benefit of HPV vaccine for 11- and 12-year-old girls and boys. The public health and medical communities recognize the equal benefits in cancer and genital wart prevention for males and females by administering, in recommended time frames, a complete HPV vaccine series. We have an opportunity to significantly improve the public’s health now and in decades to come.