The adult vaccination landscape in the United States during the Affordable Care Act era: Results from a large retrospective database analysis

Background: Early provisions of the Affordable Care Act (ACA) reduced financial barriers to preventive care, including routinely recommended vaccines; however, vaccination coverage remains suboptimal. This study examined characteristics of routine adult vaccinations and potential missed opportunities for vaccinations through the lens of healthcare resource utilization among adults in the ACA era.

Methods: This was a retrospective analysis of healthcare claims from the Truven Health MarketScan Commercial Claims and Encounters (CCAE), Medicare Supplemental (MS), and Multi-State Medicaid databases among adults aged 19 years or older. Influenza, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis), herpes zoster (HZ), and pneumococcal vaccinations were identified between 2011 and 2016. Potential missed opportunities were defined as well-visits at which individuals were age-eligible for vaccination but did not receive it, assessed during recommended windows for each vaccine. Missed encounters were defined as having no well-visits. Multivariable logistic regression was used to identify factors associated with vaccination and potential missed opportunities.

Results: Family/internal medicine and unknown/other providers administered most influenza, Tdap, and pneumococcal vaccinations, for the CCAE/MS and Medicaid cohorts, respectively. HZ vaccinations were primarily administered through pharmacies. The proportion of vaccination events increased in the pharmacy setting between 2011 and 2016. Having preventive care visits, non-well-visits, and receiving most care from a family/internal medicine practitioner were associated with increased odds of vaccination. Missed encounters were common in Medicaid enrollees. Potential missed opportunities were more prevalent in the CCAE/MS cohort than among Medicaid enrollees. Having non-well-visits was associated with a reduced likelihood of having a missed opportunity.

Conclusion: Since the ACA implementation, preventive care among adults was sporadic. Many adults had limited opportunities for vaccination. The large prevalence of missed opportunities suggests vaccination uptake could be improved. Better support for vaccination or referrals for providers who may not traditionally vaccinate could improve vaccine uptake.