A study analyzing the prevalence of human papillomavirus (HPV) in girls and women before and after the introduction of the HPV vaccine in 2006 shows that vaccinetype HPV prevalence has decreased 56% percent among girls aged 14 to 19 years.
The study shows that the vaccine works well and that the nation needs to increase vaccination rates, according to Centers for Disease Control and Prevention (CDC) director Tom Frieden, MD, MPH. He adds that only one-third of girls aged 13 to 17 years in the United States have been fully vaccinated against HPV, representing 50,000 girls alive today who will develop cervical cancer in their lifetime due to low vaccination rates.
The study, conducted by Lauri Markowitz, MD, and her colleagues at the CDC, was published in the Journal of Infectious Diseases. The researchers used the National Health and Nutrition Examination Survey (NHANES) data to compare prevalence (or the percentage of girls and women aged 14 to 59 years with certain types of HPV) before the start of the vaccination program (2003-2006) with the prevalence after vaccine introduction (2007-2010). The study also confirmed the results of the clinical trials conducted before the vaccine was licensed, demonstrating that it was highly effective.
The decline in HPV vaccine-type prevalence is higher than experts expected, says Dr. Markowitz. She attributes it to herd immunity, high effectiveness with less than a complete 3-dose series, and/or changes in sexual behavior that could not be measured. Nevertheless, public health experts and clinicians hope to see more individuals become vaccinated against the virus. Although routine vaccination for both boys and girls at ages 11 and 12 years is recommended, only approximately onehalf of all girls in the United States and far fewer boys received the first dose of HPV vaccine.