During the past 10 years, rates of cancer-causing human papillomavirus dropped dramatically among American teenagers. The reason for this decrease is largely because of a widespread rollout of the HPV vaccine, shows a new report from the U.S. Centers for Disease and Prevention (CDC), published in the journal Pediatrics, CNN reports.

For the study, researchers at the CDC compared the rates of HPV infection in women ages 14 to 34 between 2003 and 2006 (the three years before the vaccine was recommended) with the most recent years for which data are available, 2009 to 2012. 

Results showed that among girls ages 14 to 19, rates of infection with the four strains of virus the HPV vaccine currently protects against dropped nearly 63 percent. What’s more, scientists found that among vaccinated sexually active women ages 14 to 24, rates of infection with these HPV strains were only 2.1 percent, compared with 16.9 percent among their unvaccinated counterparts. 

“These results are very encouraging and show the effectiveness of the vaccine,” said Lauri E. Markowitz, MD, PhD, a medical epidemiologist at the CDC, and the study’s lead author. “Eventually, we expect to see decreases in HPV in older groups as women who were young (enough to get the vaccine) age.” 

Currently, doctors recommend the three-dose HPV vaccine for girls, and, as of 2011, also boys, ages 11 to 12. Docs also recommend the vaccine for women and men up to ages 26 and 21 respectively. 

For more information about the HPV vaccine and how it helps prevent cervical cancer, click here.