Epidemiological characteristics and societal burden of varicella zoster virus in the Netherlands

Abstract

BackgroundVaricella and herpes zoster are both caused by varicella zoster virus (VZV) infection or reactivation and may lead to complications associated with a (severe) societal burden. Because the epidemiology of VZV-related diseases in the Netherlands remains largely unknown or incomplete, the main objective of this study was to study the primary care incidence, associated complications and health care resource use.MethodsWe investigated the incidence of VZV complications in the Dutch general practitioner (GP) practices and pharmacies in a retrospective population-based cohort study (2004–2008) based on longitudinal GP data including free text fields, hospital referral and discharge letters from approximately 165,000 patients.ResultsThe average annual incidence of varicella GP-consultations was 51.5 per 10,000 (95% CI 44.4-58.7) overall; 465.5 per 10,000 for 0–1 year-olds; 610.8 per 10,000 for 1–4 year-olds; 153.5 per 10,000 for 5–9 year-olds; 8,3 per 10,000 for >10 year olds. When only ICPC coded diagnoses were analyzed the incidence was 27% lower. The proportion of complications among varicella patients was 34.9%. Most frequently complications were upper respiratory tract infections. Almost half of the varicella patients received medication. The referral rate based on GP consultations was 1.7%. The average annual incidence of herpes zoster GP-consultations was 47.5 per 10,000 (95% CI 40.6-54.4). The incidence increased with age; 32.8 per 10,000 for <60 year-olds; 93.1 per 10,000 for 60–64 year-olds and 113.2 per 10,000 for >65 year olds. When estimating herpes zoster incidence only on ICPC coded information, the incidence was 28% lower. The complication rate of herpes zoster was 32.9%. Post herpetic neuralgia was seen most often. Of patients diagnosed with herpes zoster 67.8% received medication. The referral rate based on GP consultations was 3.5%.ConclusionsFor varicella the highest incidence of GP-consultations was found in 1–4 year-olds, for herpes zoster in the >65 years olds. The occurrence of complications was not age-dependent but varies per complication. When estimating incidence of VZV-related diseases in primary care, based on diagnostic codes only, one should be aware of a gross underestimation of the incidence. Our analysis may have important implications for the outcomes of upcoming cost-effectiveness analyses on VZV vaccination.

Estimation of the burden of varicella in Europe before the introduction of universal childhood immunization

“…The most frequently found unique data source was on seroprevalence ( n  = 52) [17–68], followed by hospitalisation ( n  = 39) [23, 27, 40, 69–104], primary care ( n  = 27) [7, 8, 23, 27, 74, 76, 78–81, 97, 99, 102, 104–117], mortality ( n  = 15) [11, 23, 27, 74–76, 79, 80, 84, 91, 97, 118–121], and incidence of reported varicella cases through mandatory surveillance ( n  = 14) (Table 1) [5, 26, 27, 40, 79, 80, 101, 116, 122–127]. Varicella community incidence was estimated from 43 seroprevalence data sources from 16 countries [17–27, 29–41, 44–47, 49–54, 57–62, 64, 65, 68], primary care incidence from 17 PCI data sources from 8 countries [23, 74, 76, 79, 80, 99, 101, 102, 104–106, 109, 110, 112, 114, 124, 126], hospitalisation incidence from 18 HI data sources from 10 countries [23, 69–73, 75, 76, 79–81, 84, 87, 90, 91, 94, 102, <...>…”

“…Varicella community incidence was estimated from 43 seroprevalence data sources from 16 countries [17–27, 29–41, 44–47, 49–54, 57–62, 64, 65, 68], primary care incidence from 17 PCI data sources from 8 countries [23, 74, 76, 79, 80, 99, 101, 102, 104–106, 109, 110, 112, 114, 124, 126], hospitalisation incidence from 18 HI data sources from 10 countries [23, 69–73, 75, 76, 79–81, 84, 87, 90, 91, 94, 102, 103], and one data source was used to estimate mortality in 31 countries [11] (Table 2). Data on all four outcomes was only available for six countries (Belgium, France, Italy, the Netherlands, Spain and the UK).…”

Sociodemographic characteristics and chronic medical conditions as risk factors for herpes zoster

“…2,8,27,28,[32][33][34][35][36][37][38][39] Gender differences in the incidence of herpes simplex add strong support to the hypothesis that females have a differing response to latent viral infection and that this may account for their increased risk compared with men. 16 Studies conducted in numerous settings, and with various designs, have indicated an association between age and increasing zoster incidence.…”

The temporal impact of aging on the burden of herpes zoster

“…Although annual incidence rates were presented for 11 studies [4–7, 9, 11, 17, 19–22], we focused on three studies as they reported the annual incidence data specifically for the ≥65 age group while also reporting incidence over a sufficiently long time period so as to perform linear best fit curve. The studies used to estimate the incidence rates were Leung et al [6], Toyama et al [7] and MacIntyre et al [4] which reported HZ incidence rates for the US, Japan and Australia respectively and was adjudged to present a reasonable picture of the expected HZ burden in high-income country setting.…”