There have been significant declines in vaccinetype human papillomavirus (HPV) infections among both vaccinated and unvaccinated adolescent girls and young adult women, according to research published in the Morbidity and Mortality Weekly Report. Researchers used data from the National Health and Nutrition Examination Survey (2017 to 2018) to assess HPV prevalence estimates among girls and women aged 14-34. Compared with the prevaccine era, the 2015-2018 period showed significant decreases in quadrivalent vaccine (4vHPV)-type prevalence among girls and women aged 14-19 (88%) and aged 20-24 (81%). There was a decrease noted in 4vHPVtype prevalence among sexually experienced females who reported receiving at least one HPV vaccine dose (97% among those aged 14-19 years; 86% among those aged 20-24), as well as among those who reported no vaccination (87% among those aged 14-19; 65% among those aged 20-24). These significant declines among unvaccinated girls and women suggest herd effects. “HPV vaccination is a critical prevention tool against HPV infection, anogenital warts, and HPV-attributable precancers and cancers,” the authors write. “HPV vaccination is highly effective and is recommended routinely at age 11 to 12 years and through age 26 years for persons not already vaccinated.”