17 - Assessment of Recombinant Zoster Vaccine Second Dose Completion in the United States

Background: Recombinant Zoster Vaccine (RZV) was licensed in the United States (US) in October 2017 for the prevention of herpes zoster in adults ≥ 50 years of age (YOA). The vaccine is administered in a two-dose sequence with a 2- to 6-month interval; however, the Center for Disease Control & Prevention has advised against restarting a series after the prescribed window. This study describes an assessment of 2^nd dose completion and compliance of RZV in the US.

Methods: Primary analysis was conducted on a cohort ≥ 50 YOA who received an initial RZV dose between October 2017 and September 2018 as indicated in the IQVIA longitudinal prescription claims or medical claims databases. Subjects were required to have ≥ 1 year of observable time post initial dose. A sensitivity analysis was conducted using all eligible subjects regardless of observable time post initial dose. Endpoints of analyses were monthly and cumulative 2^nd dose label-compliant proportions at 6 months and completers by 12-month intervals and time to completion from initial RZV vaccine administration with stratifications by age, sex, claim source and payer type.

Results: The primary sample included 1,225,088 subjects, while the sensitivity analysis included 7,097,441 (Table 1). Overall, 2^nd RZV dose completion was 70.4% within 6 months and 81.8% within 12 months. Minimal variation for 12-month completion was demonstrated across age (77.2-84.5%), sex (81.7-81.9%), and Commercial vs. Medicare (80.9-83.0%). However, larger variations were seen across claim sources and other payer type, with medical claims (64.9%), Medicaid patients (72.8%) and Cash patients (74.7%) having lower rates at 12 months (Table 2). Overall, the average time to completion was around 4 months regardless of stratification except by claims source, with medical claims taking 5 months on average to complete. The sensitivity analysis of the variable follow-up cohort demonstrated findings consistent with that of the primary sample.Table 1. Subject Demographics
Table 2. Primary Analysis RZV Completion by 6 and 12 Months Post Initial Vaccination


Conclusion: Assessment of RZV suggests high levels of completion across age, sex, payer type and claim sources. More effort is needed to understand barriers to completion rates in Medicaid patients and settings where vaccination claims are processed outside of the vaccine recipient’s pharmacy benefit.