Which is the better use of resources: increasing HPV vaccine uptake or developing new vaccines that protect against all oncogenic HPV strains?
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More resources should be invested in developing new HPV vaccines that protect against all oncogenic HPV strains.
When we started developing HPV vaccines 15 to 20 years ago, we were targeting cervical cancer. First-generation HPV vaccines covered approximately 70% of all cervical cancers. As the science has matured, we now know more about the types of HPV involved in carcinogenesis. Theoretically, we may be able to increase the coverage up to 100% of cervical cancers with a broader vaccine, but this will be difficult to do with our current first- and second-generation vaccines.
Moreover, 15 to 20 years ago, head and neck cancers were not on our radar as HPV-related malignancies. Although these cancers are mostly caused by HPV16, which is covered by the current vaccines, next-generation HPV vaccine clinical trials should concentrate on prevention of head and neck cancers.
We also know now that HPV5 and 8 may cause certain skin cancers. A research priority should be to find a broadly effective vaccine to cover all of these HPV types and subsequent cancers.
Additionally, a single-dose vaccine is a highly desirable goal for HPV vaccines. We have a two-dose vaccine schedule in the youngest age groups. We also want a vaccine that is less expensive than current versions, because these vaccines are out of reach in terms of cost for most of the developing world.
According to WHO, 85% of all cervical cancer deaths occur in the developing world. Several studies have shown that the early versions of the HPV vaccine have decreased cervical cancer rates. However, these initial reports are from countries with extensive health infrastructure and resources. An inexpensive, single-dose HPV vaccine with broad HPV coverage would be a global triumph against a viral infection responsible for a wide variety of cancers.
Kevin A. Ault, MD, FACOG, is professor of obstetrics and gynecology at University of Kansas Medical Center. He can be reached at kault2@kumc.edu. Disclosure: Ault reports paid consultant roles with PathoVax and Inovio.
More resources should be invested in increasing vaccine uptake.
The goal of eradication of HPV-related cancers through a vaccine program is potentially achievable but, at the current time, using additional resources to increase the uptake of the licensed and recommended 9-valent HPV vaccine will result in a greater reduction of HPV-related cancers.
According to the CDC, of the 30,700 estimated annual cases of cancer attributed to HPV, 28,500 could be prevented with the 9-valent vaccine. However, this goal cannot be reached without markedly increasing the uptake of the 9-valent vaccine among boys and girls aged 11 to 12 years.
Unfortunately, after 12 years of licensure, HPV vaccination rates have significantly lagged behind those for other vaccines recommended for this age group. The 2016 CDC survey on vaccine uptake by adolescents indicated that, by age 17 years, only 49.5% of girls and 37.5% of boys in the United States had completed the HPV vaccine series. Thus, more than 50% of older adolescents and young adults are not being protected against HPV infection before they become at risk for HPV infection.
We can achieve the largest short-term reduction in HPV-related cancers by focusing our current resources on rapidly improving 9-valent vaccine immunization rates among those aged 11 to 12 years. Modeling shows that this approach will have the greatest effect on reducing HPV-related cancers and deaths.
A number of studies have shown that parental lack of knowledge of the consequences of HPV infection and misinformation about the vaccine, its safety and its need in this age group can lead to hesitation and delay the decision to vaccinate. It also has been shown that provider perceptions of parental reluctance and provider willingness to delay vaccination have reduced uptake.
Education of parents and providers, as well as a strong recommendation by providers, have been shown to improve HPV uptake. We need to optimize the use of the HPV vaccine we have. The sooner we increase uptake, the sooner HPV-related cancers will be reduced.
Joseph A. Bocchini, MD, is professor and chairman of pediatrics, and director of the Clinical Virology Laboratory at Louisiana State University Health Sciences Center. He also is a member and past chair of the ACIP HPV Vaccine Work Group. He can be reached at jbocch@lsuhsc.edu. Disclosure: Bocchini reports no relevant financial disclosures.