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Abstract: TH-PO936

Undercounting of COVID-19 Vaccinations in Fee-for-Service Medicare Claims

Session Information

Category: Coronavirus (COVID-19)

  • 000 Coronavirus (COVID-19)


  • Roetker, Nicholas S., Hennepin Healthcare Research Institute, Minneapolis, Minnesota, United States
  • St. Peter, Wendy L., University of Minnesota Twin Cities, Minneapolis, Minnesota, United States
  • Hoover, Madison, Hennepin Healthcare Research Institute, Minneapolis, Minnesota, United States
  • Wetmore, James B., Hennepin Healthcare Research Institute, Minneapolis, Minnesota, United States
  • Johansen, Kirsten L., Hennepin Healthcare Research Institute, Minneapolis, Minnesota, United States

Older individuals and those with certain underlying conditions were among the earliest groups offered COVID-19 vaccinations. While patients with ESKD did not initially receive priority, a federal program permitted vaccinations to be administered in dialysis clinics starting in March 2021. We studied early uptake of COVID-19 vaccinations in Medicare fee-for-service beneficiaries with ESKD.


We included beneficiaries aged ≥18 years with ESKD on December 1, 2020 from the US Renal Data System. Vaccinations covered by Medicare were identified using CPT codes. The cumulative monthly incidence of first vaccination dose through June 2021 was compared by modality (HD, PD, transplant) and stratified by age and race/ethnicity. Death was treated as a competing risk.


By June 30, 2021, the cumulative incidence of receiving a Medicare-covered first vaccination dose was <40% in patients receiving HD (Figure A), well under the estimate reported by dialysis facilities to the CDC by this date (72%). Although caution is required, some interpretation of the Medicare vaccination data may still be permitted. After the allocation of vaccines to dialysis clinics, Medicare-covered vaccinations surged in patients receiving HD relative to the other modalities. In patients receiving HD, uptake of Medicare-covered vaccinations was initially highest among those aged ≥65 years and then surged in younger patients following the federal vaccine allocation (Figure B).


COVID-19 vaccination rates are severely underestimated using Medicare administrative data. It is unclear whether missingness of vaccination data is differential by demographic groups, such as race/ethnicity. Inferences based on these data should be made with caution.


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