Electra D. Paskett, PhD
EARLY IN our careers, few of us imagined that a vaccine could one day prevent cancer. Now, there is a vaccine that keeps the risks from human papillomavirus (HPV) at bay, and yet universal adoption of the HPV vaccine has been incomplete. As a result of misinformation about the vaccine—and its administration in children, adolescents, and young adults aged 9 to 26 years—combined with a three-dose schedule that has been a challenge for some parents to complete, vaccination rates in the United States have remained low.
Now, with the emergence of a two-dose regimen for preteen and teenage girls and boys aged 9 to 14, the medical community has an opportunity to revisit the conversation with parents about the benefit of the HPV vaccine and reinvigorate efforts to expand HPV vaccination in younger patients. If successful, we may save thousands of Americans from cancer every year.
A Common Virus With An Uncommon Risk
ONCOLOGISTS AND CANCER CONTROL RESEARCHERS, including my colleagues at The Ohio State University Comprehensive Cancer Center–Arthur G. James Cancer Hospital and Richard J. Solove Research Institute in Columbus, regard HPV as the leading cause of many cervical, anal, vaginal, vulvar, penile, and oropharyngeal cancers. In fact, studies are now revealing how HPV integrates into the genome and triggers the mutations leading to cancer.1
The Centers for Disease Control and Prevention (CDC) tracks HPV infections and trends, and the numbers are daunting: 79 million Americans are currently carriers of at least 1 type of HPV, and about 14 million become newly infected each year.2 Most infections are benign, and 9 of 10 fade within 2 years, but several strains have been directly linked to cancers, affecting more than 30,000 Americans annually.3
Although HPV is almost universally transmitted through sexual activity, studies have shown that the virus can also be transmitted orally through kissing. For the vaccine to be most effective, immunity against the virus must be developed well before exposure, which is why it’s important that young people are vaccinated at the full dosing schedule long before engaging in sexual activity. When properly administered, clinical trials have shown that HPV vaccines provide close to 100% protection against cervical precancerous lesions and genital warts. Over the past decade, there has been a 64% reduction in HPV infections targeted by the vaccines.2
Removing the Controversy Over Vaccination
ALMOST IMMEDIATELY FOLLOWING the U.S. Food and Drug Administration (FDA) approval of the first recombinant human HPV vaccine (Gardasil) in 2006,4 the vaccine became embroiled in dangerously incorrect assumptions—even more prevalent at that time—about vaccines and a persistent political debate that confuses the recommended age for HPV vaccination (well before a child’s first sexual encounter) with the issue of sexual activity. Despite those challenges, the publicity surrounding the vaccine has helped health-care providers raise awareness of its benefit, and vaccination rates have grown.
There is currently a nine-valent HPV vaccine (Gardasil 9) recommended for preteens and teens. The CDC recently announced that Gardasil 9 is as effective in two doses as in the previously recommended three doses for adolescents 9 to 14 years old, with the dosages separated by 6 months. As parents consider their HPV vaccine options, the two-dose approach will likely prove more convenient and easier to adhere to than the three-dose regimen. Teenagers and young adults aged 15 and older still need the full three doses over 6 months.
Educating the Public and Health-Care Providers
RECENTLY, THE 69 NATIONAL CANCER INSTITUTE (NCI)-designated cancer centers called on Americans to universally endorse the vaccine and follow the CDC’s new two-dose recommendation when appropriate. The two-dose push is critical because the latest CDC HPV vaccination statistics reveal that for teenagers aged 13 to 17, only 41.9% of girls and 28.1% of boys received the full three rounds of the HPV vaccine by the end of 2015.5
After more than a decade of use, it is clear that HPV vaccines are safe and effective. It is our role as health-care providers to help the public understand the benefit of these vaccines in the prevention of cancer. Those of us at the nation’s NCI-designated cancer centers recommend the following:
• We encourage all parents and guardians to have their sons and daughters complete a two-dose 9-valent HPV vaccine series starting before age 13 or complete a catch-up vaccine series as soon as possible in older children, including three doses of the vaccine in those older than 15.
• Adolescents and young adults who are 15 and older should continue to complete the three-dose vaccination series, even though the new CDC guidelines recommend that children 9 through 14 should receive two doses of the 9-valent HPV vaccine at least 6 months apart.
• We encourage everyone up to age 26 who was not vaccinated as a preteen or teenager to complete a three-dose vaccine series to protect against HPV.
• We encourage all health-care providers to be advocates for cancer prevention by making strong recommendations for childhood HPV vaccination. We ask providers to join forces to educate parents, guardians, and colleagues about the importance and benefits of HPV vaccination.
AS A CANCER CONTROL RESEARCHER and the parent of three boys, I have closely followed the arrival of HPV vaccines. There is no room for equivocation: These vaccines work. And given that they can prevent my children from developing cancer later in life, there was never any question that I would have them vaccinated. During the past century, vaccines helped bring many diseases under control and eradicated smallpox. Today, there exist vaccines that may help eradicate several cancers in this century—but only if we act now. ■
DISCLOSURE: Dr. Paskett has received research funding from Merck.
1. Akagi K, Li J, Broutian TR, et al: Genome-wide analysis of HPV integration in human cancers reveals recurrent, focal genomic instability. Genome Res 24:185-199, 2014.
2. Centers for Disease Control and Prevention: Human papillomavirus (HPV): Questions and answers. Available at cdc.gov/hpv/parents/questions-answers.html. Accessed August 22, 2017.
3. Centers for Disease Control and Prevention: HPV-associated cancer statistics. Available at cdc.gov/cancer/hpv/statistics/index.htm. Accessed August 22, 2017.
4. U.S. Food and Drug Administration: Approved products: Gardasil. Available at www.fda.gov/BiologicsBloodVaccines/Vaccines/ApprovedProducts/ucm094042. Accessed August 22, 2017.
5. Reagan-Steiner S, Yankey D, Jeyarajah J, et al: National, regional, state, and selected local area vaccination coverage among adolescents aged 13-17 years: United States, 2015. MMWR Morb Mortal Wkly Rep 65:850-858, 2016.