BACKGROUND: A postmarketing study (EU PAS 49836) is underway to assess use and safety of the Janssen Ad26.COV2.S COVID-19 vaccine in the United States. Understanding uptake of the Ad26.COV2.S COVID-19 vaccine and characteristics of users relative to other COVID-19 vaccines is essential for assessing comparative vaccine safety.
OBJECTIVES: To assess utilization of the Ad26.COV2.S and mRNA COVID-19 vaccines at four large national commercial insurers and to characterize recipients.
METHODS: First-time recipients of COVID-19 vaccines (Ad26.COV2.S or mRNA) aged ≥ 18 years with ≥ 1 year of prior health plan enrollment were identified from claims data within four national insurers participating in the Sentinel System from February through October 2021. Vaccinees were described by vaccine administration setting, baseline demographics, and clinical characteristics, stratified by initial COVID-19 vaccine type.
RESULTS: A total of 228,630 Ad26.COV2.S vaccinees and 2,381,098 mRNA vaccinees were identified. Among mRNA vaccinees, 80.1% had a subsequent dose recorded in the databases, and 59.3% of first doses were Pfizer-BioNTech. Most identified vaccinations occurred in outpatient pharmacies (64.0% Ad26.COV2.S, 55.7% mRNA) and ambulatory visits (33.3% Ad26.COV2.S, 42.0% mRNA). Ad26.COV2.S vaccinees were older (mean age, 48.5 vs. 47.7 years) and more likely to be male (54.2% vs. 49.0%) compared with mRNA vaccinees. The baseline prevalence of comorbidities (including diabetes, heart conditions, obesity, asthma, and immunocompromised status) and geographic distribution of vaccinees were similar between the two vaccine types. Ad26.COV2.S vaccinees were less likely to have had evidence of pregnancy at vaccine administration (2.5% vs. 3.8% of women). Ad26.COV2.S and mRNA vaccinees had similar measures of prior healthcare utilization. Less than 1% of all vaccinees received a non-COVID vaccine (e.g., influenza vaccine) on the date of their COVID-19 vaccine. Race and ethnicity data were missing or unavailable for more than 85% of vaccinees.
CONCLUSIONS: Ad26.COV2.S vaccines represented less than 9% of first COVID-19 vaccine doses observed in these data, likely due to United States Food and Drug Administration and Centers for Disease Control and Prevention’s recommendations on the use of Ad26.COV2.S. Incorporating state immunization registry data is expected to improve vaccine capture for final safety analyses. Small differences in the age and sex distribution between vaccine types may reflect channeling of men away from mRNA vaccines and targeted campaigns to use Ad26.COV2.S, a single-dose vaccine. Controlling for any population differences will be critical for inferential analyses.
