By Vijay Chawla, MD, FAAP, Mayo Clinic
Papilloma viruses are small DNA viruses that cause species- and tissue-specific disease. There are more than 200 types of human papilloma virus (HPV), which infect the skin and mucous membranes and are transmitted by contact. Lifetime risk of HPV infection exceeds 75 percent, and new HPV infections occur across the lifespan, albeit with a peak in young adulthood. While most infections clear within months, a minority produce complications.
Following FDA approval of the first HPV vaccine in 2006, the CDC Advisory Committee on Immunization Practices (ACIP) voted to recommend routine immunization for females in 2006 and for males in 2011. The current recommendation is to give three doses of vaccine to all adolescents at age 11 to 12 years. The quadrivalent and 9-valent vaccine products may be given to either sex; the bivalent product is only recommended for females. All females, and males who are immunocompromised or have sex with males, may begin the series as late as age 26. For other males, 21 is the latest recommended age for series initiation.
Despite unequivocal recommendations from ACIP, AAP, and AAFP, it has been challenging to achieve acceptance of HPV vaccine in the United States. As Figure 1 illustrates, uptake of HPV vaccine is lacking compared to other recommended vaccines. Adherence to the full 3-dose HPV series is even less prevalent than the 1-dose coverage shown.
Minnesota’s 2014 implementation of school requirements for Tdap and MCV4 at grade 7 failed to accelerate HPV uptake. Both parents and providers tend–however inaccurately–to view a school requirement as a marker of a vaccine’s importance. They may not appreciate that HPV causes about 31,000 cancers per year in the United States, the vast majority of them vaccine-preventable types.
Other countries have achieved much higher immunization rates. This may reflect their success in addressing some of the major factors believed to keep American rates low:
Provider recommendation. Parents consistently cite a health care provider’s recommendations as the most influential factor in the decision to vaccinate. Only 76 percent of providers, however, routinely recommend HPV vaccine to girls at 11-12 years, and even fewer (46 percent) routinely recommend it to boys the same age.
Parent resistance. Providers are pessimistic about recommending HPV vaccine: 55 percent believe they cannot change the minds of reluctant parents, and 47 percent don’t have time to discuss parents’ reasons for declining it. They may benefit from preparing sound responses to the top reasons parents give for declining or delaying HPV vaccine: safety concerns, the belief that the child is too young and/or not sexually active, and general lack of knowledge about the vaccine.
Stigma. Neither providers nor parents are eager to discuss sexually transmitted infections with young adolescents. CDC recommends keeping conversations about HPV vaccination simple and direct, offering the vaccine “the same way, the same day” that other adolescent vaccines are offered. It can also be helpful to frame HPV vaccine as preventing cancer rather than sexually transmitted disease.
Timing. Unfortunately, few adolescents visit health care providers as often as younger children do, so opportunities to vaccinate arise less frequently. HPV vaccine may be given as early as age 9, which allows more time to complete the 3-dose series. Sending reminder/recall letters or phone calls may improve series completion.
In summary, both providers and parents can benefit from better understanding the importance of vaccinating against HPV. Examining the factors that lead to under-vaccination may help providers protect more of their patients from preventable cancers in the future.