The Age 13 Aug 2014 – Teenage STI rate has plummeted since vaccine – The incidence of genital warts among teenage girls has plunged since schools introduced the human papilloma virus vaccination program. The largest assessment of the vaccine since schools started routinely offering it to Year 7 girls in 2007 recorded a 90 per cent drop in genital warts among 12- to 17-year-old girls in the first four years of the program and a 73 per cent drop among 18- to 26-year-old women.