19. Completion of Two-Dose Recombinant Zoster Vaccine Series in Adults 50 Years and Older
Authors: Tseng Hung-Fu , Qian Lei , Wu Jun , Luo Yi , Sy Lina S , Bruxvoort Katia , Ackerson Bradley 
Published: January 2021

Abstract

Background
In 2017, the Advisory Committee on Immunization Practices preferentially recommended adjuvanted recombinant zoster vaccine (RZV) for adults ≥ 50 years as a two-dose series 2–6 months apart.1 We evaluated two-dose RZV completion and factors associated with completion.

Methods
The study included Kaiser Permanente Southern California members ≥ 50 years who received an RZV dose during April-November 2018 and had continuous membership 12 months before to 9 months after the 1st RZV dose (RZV1). Completion was defined as receipt of the 2nd dose ≥4 weeks to 9 months after RZV1 (allowing a 3-month grace period). Characteristics including age at RZV1, sex, race/ethnicity, Medicaid status, neighborhood level income and education, distance from home to medical office, comorbidities, history of herpes zoster, health care utilization before and after RZV1, receipt of influenza vaccine, vaccination month (supply shortage proxy), concomitant vaccine, department administering RZV1, medical center, and medically attended local or systemic reaction, pain, or gout after RZV1 were compared between completers and non-completers. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) for factors associated with completion were estimated by multivariable logistic regression.

Results
Among 31,120 RZV1 recipients, 67.2% completed the series within 9 months. In adjusted analyses, higher completion was associated with White compared with Black or Hispanic race/ethnicity, higher neighborhood income and education, no chronic pulmonary disease, diabetes, or dementia, more outpatient visits and fewer emergency department visits before or after RZV1, no hospitalizations after RZV1, receipt of influenza vaccine, receipt of RZV1 in June-November rather than April-May 2018, no concomitant vaccine with RZV1, and receipt of RZV1 in Family Practice rather than Internal Medicine. Systemic reactions or pain after RZV1 was not associated with completion.
Table 2. RZV Series Completion by Selected Characteristics During Follow-up of Members Aged ≥50 Years Who Received at Least One Dose of RZV at Kaiser Permanente Southern California in April-November 2018

Table 2. RZV Series Completion by Selected Characteristics During Follow-up of Members Aged ≥ 50 Years Who Received at Least One Dose of RZV at KPSC in April-November 2018

Figure 1. Factors Associated with RZV Series Completion of Members Aged ≥ 50 Years Who Received at Least One Dose of RZV at KPSC in April-November 2018

Conclusion
Completion of RZV series appears moderate in the early phase of implementation. Despite similar accessibility in a health care system, completion varied by race/ethnicity, socioeconomic status, health status, and care seeking behavior, suggesting areas to target for improvement.

Disclosures
Hung-Fu Tseng, MPH, PhD, GlaxoSmithKlein (Research Grant or Support) Lei Qian, PhD, GlaxoSmithKlein (Research Grant or Support) Jun Wu, MD, MS, GlaxoSmithKlein (Research Grant or Support) Yi Luo, PhD, GlaxoSmithKlein (Research Grant or Support) Lina S. Sy, MPH, GlaxoSmithKlein (Research Grant or Support) Katia Bruxvoort, PhD, MPH, GlaxoSmithKlein (Research Grant or Support) Bradley Ackerson, MD, GlasoSmithKlein (Research Grant or Support)