Study: Introducing the HPV Vaccine Early Increases Likelihood of Finishing Vaccination Series

Children in clinics that start vaccinations against human papillomavirus at earlier ages are more likely to complete the vaccine series, according to new findings presented at IDWeek 2026. The HPV vaccine protects against throat, anal and several reproductive cancers. About 13 million people become infected with HPV each year, including teenagers. 

Researchers randomized clinics to introduce the vaccine at either 9-10 years or 11-12 years at 31 pediatric practices. Clinicians in all practices received training on how to best recommend the HPV vaccine, strategies to increase uptake and annual trainings on booster doses. 

Three in four children (77.1%) in clinics who began the vaccine at ages 9-10 got at least one dose and three in five (61.6%) received all doses by age 13. Comparatively, two-thirds of children (67.0%) in clinics introducing the vaccine at ages 11-12 got at least one dose and fewer than half (45.1%) received all doses by age 13. 

“Multiple factors, including the number of required vaccines for school at ages 11-12, as well as stigma around the ‘sex talk’ between providers and adolescents, have historically contributed to many children delaying vaccination against HPV,” said Sean O’Leary, MD, MPH, professor of pediatrics and infectious diseases at the University of Colorado Denver Anschutz Medical Campus and Children’s Hospital Colorado. “Lowering the age of vaccination holds promise for increasing the number of people protected against HPV, particularly as related cancers are on the rise.”  

The Food and Drug Administration approved the Gardasil 9 vaccine against HPV for people starting at 9 years old, and the Centers for Disease Control and Prevention currently recommends a two-dose vaccination series at 11 or 12 years old. The American Academy of Pediatrics recommends starting the series between 9 and 12 years, at an age the provider deems optimal for acceptance and completion of the vaccination series. 

In addition to Dr. O’Leary, study co-authors include: Allison Kempe, MD, MPH (multiple principal investigator); Dennis Gurfinkel, MPH; Christina Albertin, PhD; Alison Saville, MPH; Emma Clark, MPH; Brenda Beaty, MSPH; Sitaram Vangala, MPH; Caroline Tietbohl, PhD; and Peter Szilagyi, MD, MPH (multiple principal investigator). 

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