Szilagyi PG, Humiston SG, Stephens-Shields AJ, et al. - Researchers aimed at investigating if an online communication training in human papillomavirus (HPV) communication strategies for clinicians can aid in reducing missed opportunities for HPV vaccination, overall and at well-child care (WCC) visits and visits for acute or chronic illness (hereafter referred to as acute or chronic visits), and in increasing the rates of HPV vaccination. In this longitudinal cluster randomized clinical trial, 48 pediatric practices across 19 states were randomized to communication training or standard of care in staggered 6-month periods. Reduction in missed opportunities for HPV vaccination, particularly by improving receipt of the first HPV vaccine dose, was observed in correlation with undergoing online communication training. Findings overall suggest that rates of HPV vaccination may improve by implementing online training of pediatric clinicians focused on effective communication.