Low vaccination rates in the United States are in large part due to parental and religious objections to this vaccination that can be overcome by better education and support by pediatricians. It’s been demonstrated that physicians encourage the HPV vaccine less strongly than the other adolescent vaccinations such as Tdap and the meningococcal conjugate vaccine1. In addition, there is a lack of legislation promoting this vaccine. There are only two states and Washington, D.C., that currently have opt-out state mandates for HPV immunization, compared with 46 states plus Washington, D.C., with similar policies for Tdap2. The HPV vaccine is safe, efficacious, and has been demonstrated to reduce mortality and morbidity in our population. It is imperative that we, as pediatricians, strongly encourage and provide these vaccinations to our adolescent patients to help protect our community.
The human papillomavirus (HPV) vaccine was approved for girls in 2008 and for boys in 20113. However, the adoption rate for HPV immunization in the United States has been dismal. Data from 2014 show only 60% of adolescent girls have received at least one HPV vaccine dose, and only 40% have received three doses4. The rates for boys are far worse, with 42% of adolescent boys receiving at least one dose, and only 22% receiving three doses4.
HPV is currently the most common sexually transmitted infection in the United States, with an estimated 14 million new infections per year3. Of these, approximately 11,000 will progress to cervical cancers and 9,000 to male anogenital cancers each year. Annually there are about 4,000 cervical cancer deaths in the United States3.
Three vaccines are approved by the Food and Drug Administration to prevent HPV infection: Gardasil, Gardasil 9, and Cervarix. All three vaccines prevent infections with HPV types 16 and 18, two high-risk HPVs that cause about 70% of cervical cancers (as well as oropharyngeal and other anogenital cancers). Gardasil also prevents infection with HPV types 6 and 11, associated with approximately 90% of anogenital warts. Gardasil 9 prevents infection with the same four HPV types plus five other high-risk HPV types (31, 33, 45, 52, and 58); it is called a nonavalent, or 9-valent, vaccine.
The HPV vaccines have the ability to reduce mortality and morbidity in our patients. A study published in the New England Journal of Medicine in 2011 demonstrated that vaccination with the full HPV series in males 16-26 years prior to HPV exposure led to a 90% efficacy in preventing HPV-related disease5, compared with a 60% efficacy if given after HPV exposure or if the individual received an incomplete dose series.
A recent Pediatrics study reported data since initiation of the vaccination program in American adolescent and young adult women6. The data showed a reduction in HPV-related disease of 64% in the 14- to 19-year age group and a reduction of 34% in the older age group (aged 20-24 years). This is impressive given our currently low vaccination rates.
A Lancet meta-analysis shows evidence of herd immunity and cross-protective effects when vaccination rates are greater than 50% in the population7. This allows groups that aren’t currently approved for vaccination to have a reduction in disease and allows for some protection against HPV types that aren’t currently covered by the vaccines.
So we pediatricians have a job to do in protecting our patients by encouraging HPV immunization.
References
1. Pediatrics. 2016 Feb;137(2):1-9.
3. www.cdc.gov/hpv/hcp/clinician-factsheet.html
5. N Engl J Med. 2011;364(5):401-11.
6. Pediatrics. 2016;137(3):1-9.
7. Lancet Infect Dis. 2015;15(5):565-80.
Dr. Denby is a second-year internal medicine/pediatrics resident at Vanderbilt University Medical Center in Nashville, Tenn.
