Effectiveness of the Recombinant Zoster Vaccine in Adults Aged 50 and Older in the United States: A Claims-Based Cohort Study

Abstract

Background: The recombinant zoster vaccine had over 90% efficacy in preventing herpes zoster in clinical trials. However, its effectiveness outside of a clinical trial setting has not been investigated. This study aimed to assess the effectiveness of the recombinant zoster vaccine in general practice.

Methods: A de-identified administrative claims database, the OptumLabs Data Warehouse, was used to conduct this retrospective cohort study to assess the effectiveness of the recombinant zoster vaccine against herpes zoster in nonimmunocompromised, vaccine age-eligible individuals enrolled in the database for ≥365 days.

Results: A total of 4 769 819 adults were included in this study, with 173 745 (3.6%) adults receiving 2 valid doses of the recombinant zoster vaccine. The incidence rate of herpes zoster was 258.8 (95% confidence interval [CI], 230.0-289.4) cases per 100 000 person-years in vaccinated persons compared with 893.1 (95% CI, 886.2-900.0) in unvaccinated persons. Recombinant zoster vaccine effectiveness was 85.5% (95% CI, 83.5-87.3%) overall, with an effectiveness of 86.8% (95% CI, 84.6-88.7%) in individuals 50 to 79 years old compared with 80.3% (95% CI, 75.1-84.3%) in individuals aged 80 and older. In patients with a history of live zoster vaccine within 5 years of study inclusion, vaccine effectiveness was 84.8% (95% CI, 75.3-90.7%).

Conclusions: Recombinant zoster vaccine effectiveness against herpes zoster was high in a real-world setting. Given the low vaccine coverage and high effectiveness, a major public health effort is needed to identify and address barriers to vaccination and increase immunization rates.

Keywords: epidemiology; herpes zoster; infectious disease; real world evidence; recombinant zoster vaccine; shingrix vaccine; vaccine effectiveness.

Figure 1.

Flow diagram of inclusion and exclusion criteria for study cohort. ^aIndex date was defined as the date at which an individual was eligible for study inclusion. ^bOf the 116 153 individuals who only had a single valid dose of RZV, 106 462 (91.7%) of them completed 1 dose during the study period, with 9691 (8.3%) of the individuals having an improperly spaced second dose. ^cTwo valid doses of RZV were defined as receiving the second dose between 30 and 210 days after the first dose. Abbreviations: HZ, herpes zoster; ICD, International Classification of Diseases; OLDW, OptumLabs Data Warehouse; RZV, recombinant zoster vaccine.

Figure 2.

Recombinant zoster vaccine effectiveness by age, sex, race/ethnicity, and region from 2018 to 2019. ^aValues are reported as percentages. ^bVaccine effectiveness was adjusted using inverse probability weighting for age, sex, race, region, prior zoster vaccine live, antiviral use, healthcare utilization, and Charlson comorbidity index. ^cThe unknown race/ethnicity category includes individuals with either unknown or missing race/ethnicity. Abbreviation: CI, confidence interval.