Effectiveness of the Adjuvanted Recombinant Zoster Vaccine in Adults ≥50 Years in the United States

Abstract

Background: Recombinant zoster vaccine (RZV) was approved for adults aged ≥50 years in the United States to prevent herpes zoster (HZ) and postherpetic neuralgia (PHN). This study evaluated real-world vaccine effectiveness (VE) of RZV in adults aged ≥50 years.

Methods: A cohort study was conducted at Kaiser Permanente Southern California (KPSC). The exposed cohort included members aged ≥50 years who received 1 or 2 RZV doses 04/2018-12/2020. They were matched 1:4 with unvaccinated individuals by age, sex, and race/ethnicity, then followed until 12/2022. Adjusted VE (aVE) and 95% confidence interval (CI) were estimated via stratified Cox models for 1 dose and 2 doses against HZ (diagnostic codes B02.xx plus antiviral within 7 days) and PHN (chart review for HZ-related pain persisting >3 months). Stratified aVE by demographic characteristics, immunocompromised status, comorbidities, concomitant vaccination, and overall durability were assessed.

Results: Among N=102,766 (median age 68 years) who received 2 RZV doses (4 weeks-6 months apart), 48,028 (46.7%) had previously received zoster vaccine live; aVE was 73.9% (95% CI:71.8%-75.8%) for HZ and 83.7% (95% CI:75.1%-89.3%) for PHN. VE against HZ was comparable across individuals with concomitant vaccinations and different comorbidities. VE against HZ and PHN remained stable over 4 years post-vaccination. One-dose VE was 60.3% (56.4%-63.9%) against HZ and 45.6% (11.4%-66.6%) against PHN.

Conclusions: Two doses of RZV were effective in preventing HZ and PHN in adults aged ≥50 years, with durable protection. These findings underscore the importance of adhering to the recommended vaccination schedule.

Keywords: Adult Vaccination; Herpes Zoster; Herpes Zoster Vaccine; Vaccine Effectiveness.