Modelling the impact of a combined varicella and zoster vaccination programmeArchived

Modelling the impact of a combined varicella and zoster vaccination programme on the epidemiology of varicella zoster virus in England Van Hoek AJ, Melegaro A, Zaghenid EW, Edmunds J, Gay N. Vaccine 2011; 29: 2411–20.

This study updates previous work on modelling the incidence of varicella and Herpes Zoster (HZ) following the introduction of childhood varicella vaccination. The updated model includes new data on age-specific contact patterns, as well as data on the efficacy of zoster vaccination in the elderly, and allows for HZ among vaccinees. The current study also looks at two-dose varicella childhood programmes, and assesses the combined impact of varicella vaccination in childhood and zoster vaccination of the elderly.

The results suggest that a single-dose policy may result in significant numbers of breakthrough cases, a pattern which has been observed in the US. A two-dose schedule is likely to lead to a low incidence of varicella, provided coverage is maintained at around 90% for the first dose. An increase in HZ incidence is still expected following varicella vaccination in childhood, and this increase could only be partly ameliorated by introduction of HZ vaccination in the elderly. However, the effectiveness of this combined strategy is limited, as much of the increase occurs in those adults too young to be vaccinated.