ATLANTA, June 20 (UPI) -- The vaccine against human papillomavirus infections is more effective than expected, but only a third of U.S. girls age 13-17 are vaccinated, officials say.
The study, published in The Journal of Infectious Diseases, found since the vaccine was introduced in 2006, vaccine-type HPV prevalence decreased 56 percent among females ages 14-19.
The Centers for Disease Control and Prevention said each year 19,000 cancers caused by HPV occur in women -- cervical cancer is the most common in U.S. women -- while, about 8,000 cancers caused by HPV occur each year in U.S. men with oral cancer the most common.
About 79 million Americans, most in their late teens and early 20s, are infected with HPV and each year, about 14 million people become newly infected, the CDC said.
"This report shows that HPV vaccine works well, and the report should be a wake-up call to protect the next generation by increasing HPV vaccination rates," Dr. Tom Frieden, director of the CDC, said in a statement.
"The U.S. low vaccination rate represent 50,000 preventable tragedies -- 50,000 girls alive today will develop cervical cancer over their lifetime that would have been prevented if we reach 80 percent vaccination rates."
For every year the U.S. delays HPV vaccination, another 4,400 girls will develop cervical cancer in their lifetimes, Frieden said.
Dr. Lauri Markowitz and colleagues at the CDC used the National Health and Nutrition Examination Survey data to compare prevalence, or proportion of girls and women, age 14-59 with certain types of HPV -- before the start of the HPV vaccination program from 2003-06 with the prevalence after vaccine introduction from 2007-10.
"The decline in vaccine type prevalence is higher than expected and could be due to factors such as to herd immunity, high effectiveness with less than a complete three-dose series and/or changes in sexual behavior we could not measure," Markowitz said.