Today CDC reported that the prevalence of vaccine-type human papillomavirus (HPV) declined by 56% among U.S. girls aged 14 to 19 years since 2006—when routine vaccination against HPV began.
The results were revealed in an article published in the June 19 Journal of Infectious Diseases.
Using data from the National Health and Nutrition Examination Survey, Markowitz and colleagues from CDC analyzed changes in HPV prevalence for female teenagers age 14 to 19 years before (2003–06) and after (2007–10) HPV vaccine introduction. The authors reported that vaccine-type HPV (i.e., HPV-6, -11, -16, or -18) prevalence dropped from 11.5% in 2003–06 to 5.1% 2007–10.
"These are striking results. They should be a wake-up call that we need to increase vaccination rates, because we can protect the next generation of adolescents and girls against cancer caused by HPV," said Tom Frieden, MD, MPH, CDC Director, during a telebriefing.
The "wake-up call" to which Frieden referred is that despite these positive results in teenage girls, HPV vaccination rates remain less than optimal.
"Unfortunately, only one-third of 13- to 17-year-old girls in the U.S. have gotten the recommended dose series of HPV vaccine," said Frieden. "Countries including Rwanda have vaccinated a higher percentage in the target population than we have in the U.S. This is simply unacceptable. Our low vaccination rates represent 50,000 preventable deaths—50,000 girls alive today will develop cervical cancer that would have been prevented if we had reached our goal of 80% vaccination rate."
For other age groups included in the CDC study, HPV prevalence did not change significantly between the two time periods, the authors reported.
In addition, similar to clinical trials before the HPV vaccine was licensed, the study also showed the HPV vaccine to be highly effective (82%).
Currently, two HPV vaccines are licensed by FDA: Cervarix (GlaxoSmithKline) and Gardasil (Merck).
CDC noted that it will continue to analyze this sharp decrease of HPV prevalence in girls 14 to 19 years of age, as other factors such as herd immunity, high effectiveness with less than a complete three-dose vaccine series, and/or changes in sexual behavior could have influenced the results reported in today's study.
HPV is the most common sexually transmitted infection in the United States and can cause serious health problems, such as cancer, in both women and men. Frieden stated that rates of HPV-associated oral, head, and neck cancers have increased in recent years, particularly among men. About 79 million Americans are infected with HPV, with approximately 14 million new infections occurring each year.
Additional information, including who should get the HPV vaccine and at what age, is available at the CDC HPV webpage.