Vaccination Coverage of Adolescents With Chronic Medical Conditions.

INTRODUCTION: Adolescents with chronic medical conditions (CMCs) are at increased risk of vaccine-preventable infections. Little is known about their vaccine uptake.

METHODS: This retrospective cohort study included 3,989 adolescents aged 11-17 years receiving care at academically affiliated pediatric clinics between August 2011 and June 2013. Data were abstracted from the medical center's electronic health record and immunization registry in 2014. Vaccination coverage, timeliness, and missed opportunities were evaluated and analyzed in 2015-2016.

RESULTS: Adolescents with CMCs had lower human papillomavirus vaccination initiation than those without CMCs (81.3% vs 85.0%), although this difference was only observed in stratified analysis among males (adjusted relative risk=0.90, 95% CI=0.85, 0.96), aged 13-17 years (adjusted relative risk=0.94, 95% CI=0.91, 0.98), and those with more primary care visits (adjusted relative risk=0.94, 95% CI=0.91, 0.98). Adolescents with CMCs had greater influenza vaccination coverage and timeliness than those without CMCs (2011-2012 season: 66.9% vs 50.1%; adjusted hazards ratio=1.27, 95% CI=1.15, 1.40; 2012-2013 season: 73.8% vs 64.5%; adjusted hazards ratio=1.20, 95% CI=1.10, 1.31). Only 32.1% and 18.2% of eligible adolescents had received pneumococcal polysaccharide and 13-valent pneumococcal conjugate vaccines, respectively. Missed opportunities were higher among adolescents with versus without CMCs for human papillomavirus vaccination initiation (4.2 vs 2.7, p<0.001), meningococcal vaccination (4.0 vs 2.9, p<0.001), and influenza vaccination (2011-2012 season: 2.1 vs 1.7, p<0.001; 2012-2013 season: 2.0 vs 1.6, p<0.001). Missed opportunities for pneumococcal vaccination were common.

CONCLUSIONS: Pockets of undervaccination and missed opportunities exist among adolescents with CMCs. Greater, more timely influenza vaccination suggests that optimal vaccination of high-risk adolescents is possible.