Zoster Vaccine Effectiveness Against Incident Herpes Zoster and Post-Herpetic Neuralgia In Elderly In The UK

Abstract

Herpes zoster (HZ) is a painful skin rash that occurs most frequently in older adults and is caused by reactivation of latent varicella zoster virus (VZV). Its most common complication is post-herpetic neuralgia (PHN). The UK introduced zoster vaccination in the national immunization program in 2013. The vaccine was routinely offered to 70 year-olds and, as part of the catch-up, to 79 year-olds. This study assessed the vaccine effectiveness (VE) against HZ and PHN in elderly within the total population. This retrospective cohort study included subjects from birth cohorts 1943-1946 (routine) and 1934-1937 (catch-up) in the UK Clinical Practice Research Datalink (CPRD). Vaccinated subjects were compared to unvaccinated subjects using piecewise Cox regression model. HZ outcomes in community setting were analyzed, including HZ, PHN and other HZ complications (i.e. neurological but not PHN, ocular, disseminated and other). For the routine birth cohorts (79274 subjects), we found a VE for HZ of 76.4% (95% CI: 70.6%-81.1%) and for PHN of 68.3% (95% CI: 7.4%-89.1%) for the first 2 years of vaccination. For the subsequent 2+ years, the VE estimates of HZ was 56.1% (95% CI: 29.2%-72.7%). For the catch-up cohorts (48193 subjects), the VE estimates were comparable. We found insufficient evidence to determine the VE for other HZ complications. Within the total population, the HZ vaccine provided protection against HZ and PHN, but its protection declined over time. Immunosuppressed conditions need to be taken into account.