The impact of HPV vaccination is increasing in the United States, with evidence of herd protection, according to a study published in the Annals of Internal Medicine. Hannah G. Rosenblum, MD, and colleagues estimated vaccine impact and effectiveness against quadrivalent HPV vaccine (4vHPV)-type prevalent infection among sexually experienced US females and vaccine effectiveness among sexually experienced US males using data from the 2003-2006 (prevaccine era) and in 2007-2010, 2011-2014, and 2015-2018 (vaccine eras). Cervicovaginal and penile specimens were tested for HPV DNA; the prevalence rates of 4vHPV and non-4vHPV types were estimated for females in each era and for males in 2013-2016. The impact on 4vHPV-type prevalence in 2015-2018 was 85% among sexually experienced females aged 14-24, and the impacts were 90% and 74% among vaccinated and unvaccinated females, respectively. During the vaccine eras, vaccine effectiveness varied from 60% to 84% for females and was 51% for males during 2013-2016.