Incidence of Herpes Zoster, Before and After Varicella-Vaccination-Associated Decreases in the Incidence of Varicella, 1992–2002

Centers for Disease Control and Prevention, Atlanta, Georgia 30345, USA.
The Journal of Infectious Diseases (Impact Factor: 6). 07/2005; 191(12):2002-7. DOI: 10.1086/430325
Source: PubMed


Varicella zoster virus (VZV) causes varicella and, later in the life of the host, may reactivate to cause herpes zoster (HZ). Because it is hypothesized that exposure to varicella may boost immunity to latent VZV, the vaccination-associated decrease in varicella disease has led some to suggest that the incidence of HZ might increase. We assessed the impact that varicella vaccination has on the incidence of varicella and of HZ.
Codes for cases of varicella and of HZ in an HMO were determined in automated databases of inpatients and outpatients, on the basis of the Ninth Revision of the International Classification of Diseases. We calculated the incidence, during 1992-2002, of varicella and of HZ.
The incidence of HZ remained stable as the incidence of varicella decreased. Age-adjusted and -specific annual incidence rates of varicella decreased steadily, starting with 1999. The age-adjusted rates decreased from 2.63 cases/1000 person-years during 1995 to 0.92 cases/1000 person-years during 2002; among children 1-4 years old, there was a 75% decrease between 1992-1996 and 2002. Age-adjusted and -specific annual incidence rates of HZ fluctuated slightly over time; the age-adjusted rate was highest, at 4.05 cases/1000 person-years, in 1992, and was 3.71 cases/1000 person-years in 2002.
Our findings revealed that the vaccination-associated decrease in varicella disease did not result in an increase in the incidence of HZ. These early findings will have to be confirmed as the incidence of varicella disease continues to decrease.

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    • "This could have significant public health consequences, if a universal mass VZV vaccination program is implemented in childhood. Although this issue is still controversial and there is no firm evidence that this increase will occur [24-26], monitoring of disease trends over time will help understand the impact of different factors upon the incidence of HZ. In the Valencian Community (Spain), varicella vaccination is recommended and funded at 12 years of age in those subjects who have not been in clear contact with the virus. "
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    ABSTRACT: Epidemiologic data of Herpes Zoster (HZ) disease in Spain are scarce. The objective of this study was to assess the epidemiology of HZ in the Valencian Community (Spain), using outpatient and hospital electronic health databases. Data from 2007 to 2010 was collected from computerized health databases of a population of around 5 million inhabitants. Diagnoses were recorded by physicians using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM). A sample of medical records under different criteria was reviewed by a general practitioner, to assess the reliability of codification. The average annual incidence of HZ was 4.60 per 1000 persons-year (PY) for all ages (95% CI: 4.57-4.63), is more frequent in women [5.32/1000PY (95%CI: 5.28-5.37)] and is strongly age-related, with a peak incidence at 70-79 years. A total of 7.16/1000 cases of HZ required hospitalization. Electronic health database used in the Valencian Community is a reliable electronic surveillance tool for HZ disease and will be useful to define trends in disease burden before and after HZ vaccine introduction.
    BMC Infectious Diseases 10/2013; 13(1):463. DOI:10.1186/1471-2334-13-463 · 2.61 Impact Factor
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    • "In the literature, there are conflicting data with regard to whether age-adjusted HZ incidence is changing over time [7,58]. Indeed, the literature fails to show evidence of any change of HZ incidence over time, notably in relation to varicella vaccination. "
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    ABSTRACT: Background Herpes zoster (HZ) is caused by reactivation of the varicella-zoster virus (VZV) and mainly affects individuals aged ≥50 years. The forthcoming European launch of a vaccine against HZ (Zostavax®) prompts the need for a better understanding of the epidemiology of HZ in Europe. Therefore the aim of this systematic review was to summarize the available data on HZ incidence in Europe and to describe age-specific incidence. Methods The Medline database of the National Library of Medicine was used to conduct a comprehensive literature search of population-based studies of HZ incidence published between 1960 and 2010 carried out in the 27 member countries of the European Union, Iceland, Norway and Switzerland. The identified articles were reviewed and scored according to a reading grid including various quality criteria, and HZ incidence data were extracted and presented by country. Results The search identified 21 studies, and revealed a similar annual HZ incidence throughout Europe, varying by country from 2.0 to 4.6/1 000 person-years with no clearly observed geographic trend. Despite the fact that age groups differed from one study to another, age-specific HZ incidence rates seemed to hold steady during the review period, at around 1/1 000 children <10 years, around 2/1 000 adults aged <40 years, and around 1–4/1 000 adults aged 40–50 years. They then increased rapidly after age 50 years to around 7–8/1 000, up to 10/1 000 after 80 years of age. Our review confirms that in Europe HZ incidence increases with age, and quite drastically after 50 years of age. In all of the 21 studies included in the present review, incidence rates were higher among women than men, and this difference increased with age. This review also highlights the need to identify standardized surveillance methods to improve the comparability of data within European Union Member States and to monitor the impact of VZV immunization on the epidemiology of HZ. Conclusions Available data in Europe have shortcomings which make an accurate assessment of HZ incidence and change over time impossible. However, data are indicative that HZ incidence is comparable, and increases with age in the same proportion across Europe.
    BMC Infectious Diseases 04/2013; 13(1):170. DOI:10.1186/1471-2334-13-170 · 2.61 Impact Factor
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    • "Yet, after 7 years (2000–2006) of HZ surveillance, the CDC would only report, " Data are inconclusive regarding an effect of the varicella vaccination program on herpes zoster epidemiology " [9]. A CDC study which found no increase in HZ incidence [10] was severely criticized since it was conducted in a population where varicella-vaccination coverage was not widespread in the community [11]. Two additional studies in 2011 reported no evidence of the universal varicella vaccination program contributing to increases in HZ in the US [12] and Canada [13]. "
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    ABSTRACT: In a cooperative agreement starting January 1995, prior to the FDA's licensure of the varicella vaccine on March 17, the Centers for Disease Control and Prevention (CDC) funded the Los Angeles Department of Health Services' Antelope Valley Varicella Active Surveillance Project (AV-VASP). Since only varicella case reports were gathered, baseline incidence data for herpes zoster (HZ) or shingles was lacking. Varicella case reports decreased 72%, from 2834 in 1995 to 836 in 2000 at which time approximately 50% of children under 10years of age had been vaccinated. Starting in 2000, HZ surveillance was added to the project. By 2002, notable increases in HZ incidence rates were reported among both children and adults with a prior history of natural varicella. However, CDC authorities still claimed that no increase in HZ had occurred in any US surveillance site. The basic assumptions inherent to the varicella cost-benefit analysis ignored the significance of exogenous boosting caused by those shedding wild-type VZV. Also ignored was the morbidity associated with even rare serious events following varicella vaccination as well as the morbidity from increasing cases of HZ among adults. Vaccine efficacy declined below 80% in 2001. By 2006, because 20% of vaccinees were experiencing breakthrough varicella and vaccine-induced protection was waning, the CDC recommended a booster dose for children and, in 2007, a shingles vaccination was approved for adults aged 60years and older. In the prelicensure era, 95% of adults experienced natural chickenpox (usually as children)-these cases were usually benign and resulted in long-term immunity. Varicella vaccination is less effective than the natural immunity that existed in prevaccine communities. Universal varicella vaccination has not proven to be cost-effective as increased HZ morbidity has disproportionately offset cost savings associated with reductions in varicella disease. Universal varicella vaccination has failed to provide long-term protection from VZV disease.
    Vaccine 05/2012; 31(13). DOI:10.1016/j.vaccine.2012.05.050 · 3.62 Impact Factor
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