Shingles (herpes zoster) occurs in response to the triggering of the varicella zoster virus (VZV), commonly known as chicken pox (NHS England, 2023). After having chicken pox, normally in childhood, VZV lays dormant in the nervous system, establishing a permanent laten infection. Reactivation of the latent infection — typically due to immunosenescence (age-related decline in the immune response), immunosuppression or stressors such as bereavement — causes shingles (Saleh et al, 2025).

The overall prevalence in the UK is estimated to be 1.85–3.9 cases per 1000 population, increasing with age from less than two cases per 1000 in people younger than 50 years to 11 cases per 1000 in people aged 80 years or older (BMJ Best Practice, 2024). In people aged 70–79 years, the annual incidence in England and Wales is around 790–880 cases per 100,000 people (UK Health Security Agency [UKHSA], 2025a).