The vaccine program began in BC in 2008 for girls in sixth to ninth grade, and those in sixth grade in 2011. The team analyzed data on almost 300,000 girls who completed the BC Adolescent Health survey, which asked school-children about their emotional and physical health in 2003, 2008 and 2013. The girls self-identified as heterosexual.

From 2003 to 2013, the proportion of girls who had sex dropped from 21.3 to 18.3 percent. Girls who had sex before the age of 14, and substance use before intercourse “dropped significantly,” the authors of the study wrote. Girls were more likely to use condoms and contraception in 2013 than 2003. Rates of pregnancies fell, while the average number of sexual partners remained largely the same.

Study co-author Dr. Elizabeth Saewyc, of the School of Nursing, at the University of British Columbia, told Newsweek: “These findings are consistent with studies in Scandinavia, and smaller clinic-based studies in the U.S., that confirm that adolescent young women do not make poor sexual health choices after the HPV vaccine. Teens today make healthier decisions about sex than their older peers—or even their parents.”