Drop in HPV Rates in Unvaccinated Woman Shows Benefit of Herd Immunity
HealthDay News — From 2009-2010 to 2013-2014 there was a decrease in the prevalence of vaccine-type human papillomavirus (HPV) among unvaccinated young women aged 18 to 26 years, according to a study published online September 7 in Obstetrics & Gynecology.
Abbey B. Berenson, MD, PhD, from the University of Texas Medical Branch in Galveston, and colleagues examined changes in prevalence of vaginal HPV between 2009-2010 and 2013-2014 among U.S. women aged 18 to 59 years.
The researchers found that the prevalence of vaccine-type HPV decreased significantly from 2009-2010 to 2013-2014 among women aged 18 to 59 years. When the sample was stratified into four age groups, this decline was significant only among those aged 18 to 26 years. HPV prevalence remained low from 2009-2010 to 2013-2014 (3.9 to 2%) among vaccinated 18- to 26-year-olds (prevalence ratio, 0.51; 95% confidence interval, 0.18 to 1.46). A significant decrease over time was seen among unvaccinated women aged 18 to 26 years, from 19.5% in 2009-2010 to 9.7% in 2013-2014 (prevalence ratio, 0.44; 95% confidence interval, 0.22 to 0.91). Among unvaccinated women aged 26 years or older, prevalence did not change significantly.
"The decline in HPV infections among unvaccinated 18- to 26-year-old women suggests that young women in the United States are beginning to benefit from herd immunity resulting from the introduction of the HPV vaccine," the authors write.