Year of Publication
Understanding trends in vaccine refusal is critical to monitor as small declines in vaccination coverage can lead to outbreaks of vaccine-preventable diseases. Using electronic heath record (EHR) data from the Children's Hospital of Philadelphia's 31 outpatient primary care sites, we created a cohort of 403,448 children less than age 20 years who received at least one visit from 1 January 2013 through 31 December 2020. The sample represented 1,449,061 annualized patient and 181,131 annualized preventive vaccination visits per year. We characterized trends in vaccine refusal and acceptance using a repeated cross-sectional observational analysis of electronic health records (EHR) data using a single annual merged observation measure for patients seen multiple times for preventive healthcare within a calendar year. Refusals were identified for 212,900 annualized patient-visit year observations, which represented 14.6% of annualized patient-visit year observations and 25.1% of annualized vaccine patient-year observations. The odds of having a refusal marker were significantly increased in patients seen in suburban practices (aOR [CI]: 2.35 [2.30-2.40, < 0.001]), in patients with increased age 11-17 years (aOR [CI]: 3.85 [3.79-3.91], < 0.001), and those eligible for the VFC program (aOR [CI]: 1.10 [1.08-1.11]. Parental refusal (61.0%) and provider decisions (32.0%) were the most common documented in progress notes for not administering vaccines, whereas contraindications (2.5%) and supply issues (1.8%) were the least common. When offered, vaccine acceptance increased for human papillomavirus, hepatitis B, measles-mumps-rubella-containing and varicella-containing vaccines and decreased for hepatitis A and meningococcal vaccines. Repeated offering of vaccines was central to increasing acceptance, in part due to increased opportunities to address specific concerns.