Herpes zoster-associated mortality in Europe: a systematic review.

BACKGROUND: Reactivation of latent varicella zoster virus, partly due to age-related immunosenescence and immunosuppressive conditions, results in herpes zoster (HZ) and its associated complications. The management of the most important complication, post-herpetic neuralgia (PHN), is challenging, particularly in the elderly, and is generally unsatisfactory. No previous reviews have reported the incidence of HZ-associated mortality. METHODS: We carried out a systematic literature review to identify studies and databases providing data for HZ-associated mortality in adults aged ≥ 50 years in Europe. RESULTS: We identified 12 studies: Belgium (1); France (1); Germany (1); the Netherlands (2); Portugal (1); Spain (4) and England/Wales (2) and 4 databases from Europe: France; Germany and England/Wales. The incidence was available from eight studies; it was highest in those aged ≥ 95 in France (19.48/100,000). In the European (WHO) database, the overall mortality ranged from 0 to > 0.07/100,000. The age- and gender-specific HZ mortality rates from the other databases showed that while in younger age groups the HZ mortality rate was higher in males, in older patients the rate was much higher in women. The case fatality rate was 2 and 61/100,000 in those 45-65 and ≥ 65 years, respectively. A similar increase with age was seen for the hospital fatality rate; 0.6% in those 45-65 years in the UK and 7.1% in those ≥ 80 in Spain. CONCLUSIONS: Although the data were sparse and heterogeneous, HZ-associated mortality clearly increases with age. In addition, the elderly who develop HZ often have underlying diseases and are at increased risk of functional decline and loss of independence. Mortality should be taken into account in health-economics models.

Estimating the number needed to vaccinate to prevent herpes zoster-related disease, health care resource use and mortality.

BACKGROUND: A clinical trial has shown that a live-attenuated varicella-zoster virus vaccine is effective against herpes zoster (HZ) and post-herpetic neuralgia (PHN). The aim of the study was to estimate the number needed to vaccinate (NNV) to prevent HZ-related outcomes. METHODS: A cohort model of HZ associated disease, health care resource use and mortality was developed. Canadian population-based data were used to estimate age-specific incidence, hospitalization, quality-adjusted life-year (QALY) lost and mortality. NNV was calculated as the number of individuals needed to be vaccinated to prevent a specific HZ-related outcome during their lifetime. Different ages at vaccination were examined and probabilistic sensitivity analysis was performed. RESULTS: For 65 year olds, the NNV (HZ vaccine efficacy=63%, PHN vaccine efficacy=67%, no waning) to prevent a case of HZ, a case of PHN, a HZ death, a life-year lost and a QALY lost is estimated to be 11 (90% Crl: 10-13), 43 (90% Crl: 33-53), 23,319 (90% Crl: 15,312-33,139), 3762 (90% Crl: 1650-4629) and 165 (90% Crl: 105-197), respectively. Results were most sensitive to the duration of vaccine protection and the age at vaccination. DISCUSSION: The predicted NNV to prevent HZ and PHN are low even though vaccine efficacy is between 50-70%, which reflects the high incidence of these diseases among older adults. Results clearly show that the main benefit of HZ vaccination is prevention of morbidity caused by pain (as measured by QALYs lost) rather than mortality.