Adult adherence to multi-dose vaccine schedules: A population-based assessment of guideline concordance

Pneumococcal vaccination provides an accessible intervention to prevent pneumococcal infections. Approval of the 13-valent conjugate (PCV-13) with the existing 23-valent polysaccharide vaccine for adults resulted in cumbersome recommendations for 2-3 doses with complex spacing. Given these challenging logistics, we evaluated pneumococcal vaccination frequencies and guideline concordance. The objective was to determine concordance with pneumococcal vaccine guidelines among distinct at-risk groups and factors associated with and reasons for discordance.

Retrospective, population-based cohort study.

Records were reviewed for PCV-13 and/or PPSV-23 vaccination frequency and timing among vaccine-eligible adults aged ≥65 years (153,525 [57.1%]) and 19-64 years (115, 216 [42.9%]) with at least 2 clinic visits over 4 years. Underlying conditions, vaccine type and dates were systematically extracted from electronic health records (EHR) and statewide vaccine registry for a large academic health system in Colorado, covering the period 2014-2018. Descriptive statistics were used for vaccine frequency and guideline concordance. We determined the odds ratios for concordance among subgroups and multivariable logistic regression to identify factors associated with discordance.

Vaccine uptake was 69% among those ≥65 years and 27% for those aged 19-64 years. Chronic conditions were identified in 61% and immunocompromising conditions in 39% of persons 19-64 years of age. Vaccine recommendations were followed by 30.7% and 17.2% for those aged ≥65 years and 19-64 years respectively (p < 0.001). Guideline concordance was highest among persons living with HIV-1 infection (72.3%) (OR 8.03; 95% CI, 7.33-8.79 vs. overall cohort). Inclusion of statewide vaccine registry data increased ascertainment 22% (29,774 doses) over EHR alone. Limitations were potential missed vaccinations due to administrations outside the health-system which may not be reported to state vaccine registry.

Concordance with complex national guidelines for pneumococcal vaccination was low in state-wide practices. Recent guidelines with simplified timing with one or two doses should improve these outcomes.