Adolescents can now protect themselves from six different types of cancer caused by human papillomavirus with just two shots of the HPV vaccine instead of three. In a move that public health officials have expected for a while, the Advisory Committee on Immunization Practices (ACIP) at the Centers for Disease Control and Prevention recommended that boys and girls receive two doses of the HPV vaccine at ages 11 and 12.
HPV is a virus often, but not exclusively, transmitted through sexual contact that is responsible for about 5% of all cancers in the world. The current 9-valent HPV vaccine protects against 9 strains of HPV, which are responsible for approximately 90% of all HPV-caused cancers.
Previously, the recommendation had been a first dose followed by two boosters since the first quadrivalent vaccine was approved in 2006, but data reviewed at the past several ACIP meetings has shown that the vaccine is just as effective at preventing HPV with one less injection.
“A 2-dose schedule for younger adolescents was recommended because the data have shown two doses will provide safe, effective and long-lasting protection against cancers caused by HPV,” said Nancy Messonnier, MD, director of CDC’s National Center for Immunization and Respiratory Diseases. “ACIP reviewed data from clinical trials showing two doses of HPV vaccine in younger adolescents produced an immune response similar or higher than the response in young adults who received three doses.”
Canada, Australia and several other countries have already begun recommending two doses of the vaccine, but ACIP has waited to make the same recommendation in the U.S. until the Food and Drug Administration approved the vaccine for two doses just over a week ago. Youth can receive the vaccine starting at age 9, and the two-dose regimen is recommended up to age 14. Both men and women up to age 26 can continue to get the three-dose regimen, but evidence does not show the same effectiveness in older individuals with two doses.
Past research has shown significant success with decreasing HPV infection rates among those vaccinated, and the vaccine has among the strongest safety profiles of any vaccine recommended by the CDC. Yet immunization rates have lagged for a variety of reasons, including the fact that full vaccination required three visits to the doctor’s office from adolescents who rarely have reason to visit the doctor as frequently as younger children and tend to have busier schedules with school, sports and other activities.
“The pediatricians and other people I talked to said the new recommendation is a game changer with that schedule,” said Kevin Ault, MD, a professor of OBGYN at the University of Kansas Hospital who specializes in research about the HPV vaccine. “It’ll make it easier for the doctors, easier for the parents and easier for the kids. I think it will set well into what pediatricians do every day.”
The most recent figures on HPV vaccination uptake in August revealed small but significant increases in coverage. Teen girls getting at least one dose of the vaccine increased from 60% in 2014 to 62.8% in 2015, and teen boys getting at least one dose increased from 41.7% in 2014 to 49.8% in 2015.
“We’re excited to be able to report on progress on HPV coverage in boys and even in girls,” Messonnier told me at the time. “HPV coverage is still lower than we like, but we still like to see improvements in coverage.”
In 2015, just over half (56.1%) of boys and girls combined got one or more doses of the HPV vaccine.
“It’s really the strength of the provider recommendation that’s the biggest factor in determining whether adolescents get vaccinated,” Messonnier said. “A lot of the CDC efforts right now are focused on our partner organizations and other stakeholders to educate clinicians about the disease and the vaccine but also, importantly, to educate clinicians about how to talk to parents about this vaccine. We know adolescents are coming in to see their doctors and they’re getting the meningitis and whooping cough vaccines. That’s a missed opportunity to give them a vaccine that protects against cancer.”
Among the findings in that report were that teens in the Northeast U.S. tend to have higher rates of coverage than in other parts of the country. Black and Latino teens also have higher vaccination rates than white teenagers.
One obstacle to improving rates has been providers’ uncertainty about how to talk to parents and teens about the vaccine and the risks of HPV.
“One factor is that our research shows that providers really overestimate parent concerns,” Messonnier said. "When a provider tells parents, ‘This is a vaccine that protects against cancer and I recommend it,’ parents go ahead and get it.”
It will be interesting to see if the uptick continues with one less dose and a continued emphasis on the vaccine’s ability to prevent cancer, Ault said.
“One thing that has changed over the 10 years is that many of the HPV-related cancers are going up,” Ault said. The majority of throat, neck and oral cancers are caused by HPV — about 70% of them. HPV also causes 95% of all anal cancer.
“We were talking about cervical cancer, which has ben drifting down because of Pap smears, but the other HPV cancers has been increasing, and I think that’s an important selling point.”
But the simple change of going from three to two visits to the doctor may make the biggest difference.
“We recognize that it can be a challenge to get adolescents to the doctor’s office three times a year, so anything that makes it simpler for parents should help increase completion of the series,” Messonnier said.
The complete list of HPV vaccine recommendations from the ACIP meeting are as follows: