Trends in hospital admissions for Varicella and Zoster viruses in England, 2001/2002–2010/2011: time trend study

OBJECTIVES: Varicella and Herpes Zoster are common infectious diseases. Various studies have estimated rates of infection for both manifestations of these infections; however rates of hospital admissions across the country have not previously been described. This paper presents data on hospital admissions in England for Varicella and Herpes Zoster from 2001/2002 to 2010/2011. DESIGN: Time trends study of all hospital admissions for Varicella and Herpes Zoster from 2001/2002 to 2010/2011 in England. SETTING: Hospital admissions across England from 2001/2002 to 2010/2011. PARTICIPANTS: We included all patients admitted to hospital from 2001/2002 to 2010/2011 diagnosed with Varicella and Zoster according to the International Classification of Diseases version 10 (ICD-10). MAIN OUTCOME MEASURES: The main outcome measures were admission rates by year and diagnosis and age-specific admission rates for Varicella and Zoster from 2001/2002 to 2010/2011. METHODS: We analysed data from Hospital Episode Statistics which include patient characteristics such as age which was used here in order to standardise rates to the relevant population. We also used mid-year population estimates from the Office for National Statistics for standardisation purposes. All analyses were conducted using Stata v12.0. RESULTS: The hospital admission rate for Varicella cases has risen by 1.8% over the 10-year study period. While the overall admission rates for Herpes Zoster have decreased by 4% from 2001/2002 levels. The vast majority of Varicella and Zoster admissions were not associated with any complications. CONCLUSION: The introduction of Herpes Zoster vaccine is anticipated to decrease hospital admissions in older age groups further. A repeat of this study after a further period of time would help to evaluate the impact of the introduction of Herpes Zoster vaccine in England on hospital admissions.