The prevalence of dangerous strains of the human papillomavirus — the most common sexually transmitted infection in the United States and a principal cause of cervical cancer — has dropped by half among teenage girls in the last decade, a striking measure of success for a vaccine that was introduced only in 2006, federal health officials said Wednesday.
Infection with the viral strains that cause cancer dropped to 3.6 percent among girls ages 14 to 19 in 2010, from 7.2 percent in 2006, a new study has found. The vaccine protects against strains of the HPV virus that cause 70 percent of cervical cancers.
“These are striking results,” said Thomas R. Frieden, director of the Centers for Disease Control and Prevention. “They should be a wake-up call that we need to increase vaccination rates. The bottom line is this: It is possible to protect the next generation from cancer, and we need to do it.”
The study, published in the June issue of The Journal of Infectious Diseases, covered the years 2003 to 2010. Its findings were based on a national survey conducted every two years.
Health workers did face-to-face interviews and collected vaginal swabs from more than 8,000 girls and women ages 14 to 59 that were sent to the CDC for evaluation.
The decline surprised public health experts because US vaccination rates are relatively low. Only about a third of teenage girls have been vaccinated with the full course of three doses, far lower than in other wealthy countries such as Denmark and Britain, where vaccination rates are above 80 percent. Even Rwanda, in central Africa, has reached 80 percent.
Frieden said the low vaccination rate in the United States means that 50,000 girls alive today will eventually develop fatal cervical cancer, deaths that could have been prevented if the country’s rate had been at 80 percent.