Enhancing COVID-19 vaccine effectiveness evidence generation using tokenized immunization registries

To describe a novel data ecosystem and quantify improvements in documented COVID-19 vaccine uptake using closed claims data and state vaccine registries.

De-identified data from administrative claims were linked via tokenization to state vaccine registry data from two states with mandatory vaccine reporting. COVID-19 vaccine uptake in claims alone versus supplemented with registry data was measured separately for original wildtype, BA.4/5-adapted bivalent, and XBB.1.5-adapted formulations.

There were over 9 million individuals included in each formulation distribution study period. Using claims data alone versus with additional state registry data, 20% versus 57% of individuals had documented receipt of a primary wildtype series (≥2 doses of two-dose or ≥ 1 of single-dose series), 7% versus 10% BA.4/5-adapted bivalent, and 6% versus 8% XBB.1.5-adapted COVID-19 vaccine. Most claims-based vaccination events were captured with drug, rather than procedure, codes. Individuals with Medicaid-based insurance were less likely to be captured as vaccinated in claims data.

The addition of state vaccine registries increased COVID-19 vaccine capture by 182% for primary wildtype series, 41% BA.4/5-adapted bivalent, and 38% XBB.1.5-adapted formulations. Tokenization of claims data to vaccine registries presents an opportunity for more accurate estimates of vaccine uptake and effectiveness than claims data alone.