The prevalence of vaccine-type human papillomavirus has decreased 56% among females ages 14 to 19 since the HPV vaccine was introduced in 2006, according to a study.
About 79 million Americans, most in their late teens and early 20s, are infected with HPV, according to the CDC. Each year, about 14 million people become newly infected.
About 19,000 cancers caused by HPV occur in women each year, with cervical cancer the most common, according to the CDC. About 8,000 cancers caused by HPV occur each year in men in the United States, led by oropharyngeal cancers.
CDC Director Tom Frieden, MD, MPH, noted that only a third of girls ages 13 to 17 have been fully vaccinated against HPV. Meanwhile, countries such as Rwanda have vaccinated more than 80% of teenage girls.
Frieden said the low vaccination rates represent “50,000 preventable tragedies” because 50,000 girls alive today will develop cervical cancer that would have been prevented if the CDCs goal of an 87% vaccination rate had been achieved. For each year the U.S. falls short of that rate, another 4,400 women will develop cervical cancer despite the availability of good screening, Frieden said.
“This is simply unacceptable,” he said.
For the study, published in the June issue of the Journal of Infectious Diseases, researchers used National Health and Nutrition Examination Survey data to compare the proportion of girls and women ages 14 to 59 with certain types of HPV before the start of the HPV vaccination program (2003-2006) and after vaccine introduction (2007-2010).
As expected from clinical trials before the vaccine was licensed, the study also showed that the vaccine is highly effective, the researchers reported.
“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,” said the studys lead author, Lauri Markowitz, MD, of the CDCs Division of STD Prevention. “This decline is encouraging, given the substantial health and economic burden of HPV-associated disease.”
The CDC hopes the promising results will spur more people to be vaccinated for HPV. Routine vaccination at age 11-12 for both boys and girls is recommended, but according to recent national immunization surveys, only about half of all girls in the U.S. — and far fewer boys — received the first dose of HPV vaccine. A series of three shots is recommended over six months. HPV vaccination also is recommended for older teens and young adults who were not vaccinated when younger.
“Providers are not consistently giving strong recommendations for the vaccine, particularly for younger teens, and are not encouraging vaccination at every encounter,” Frieden said. “So weve identified many missed opportunities. We need to do a better job of addressing these issues and also of informing parents.
“Parents commonly say that they dont think the vaccine is needed or that their teen is not sexually active or that they have concerns about the vaccine. In terms of waiting until teens are sexually active, I think this really misses the point. We vaccinate well before people are exposed to an infection.”
Read the study abstract: http://jid.oxfordjournals.org/content/early/2013/06/18/infdis.jit192.abstract.