Tuesday, May 11, 2004 - 11:45 AM
5427

A Population-based Study of Herpes Zoster (HZ) in Children and Adolescents Post-varicella Vaccine Licensure 2000-2003

Rachel H. Civen1, Teresa Maupin2, Huiling Xiao, Jane F. Seward, Aisha O. Jumaan, and Laurene Mascola3. (1) Acute Communicable Disease Control Program, Los Angeles Department of Health Services, 313 North Figueroa Street Room 212, Los Angeles, CA, USA, (2) Varicella Surveillance Project, County of Los Angeles Department of Health Services, 44900 N. 60th Street West, Lancaster, CA, USA, (3) Acute Communicable Disease Control Unit, County of Los Angeles Department of Health Services, 313 N. Figueroa St., Room 212, Los Angeles, CA, USA


BACKGROUND:
With varicella vaccine licensure in 1995, the CDC, in collaboration with LAC, instituted varicella active surveillance in Antelope Valley (AV). In 2000, AV added HZ surveillance for children and adolescents < 20 years. We describe the incidence of HZ in a population with high varicella vaccine coverage (> 80% in 2000).

OBJECTIVE:
The objective is to describe the epidemiology of herpes zoster in children <20 years in a population with high varicella vaccine coverage.

METHOD:
HZ active surveillance was carried out from 2000-03 by all AV reporting sites. The case definition of a verified HZ case was a “ macular-papular or vesicular rash, unilateral, involving at least one dermatome” diagnosed by a licensed medical provider. For each HZ case, a standardized case report was completed. All data were placed in ACCESS and analyzed using SAS software package. HZ incidence rates were calculated using 2000-02 U.S. census data for each respective year; for 2003,2002 census data was used.

RESULT:
A total of 236 HZ cases were reported in AV from 2000-3. The overall HZ incidence for cases <20 years declined over the study period but was not statistically significant. However, there was a statistically significant decline in cases < 10 years from 40 cases (74/100,00) in 2000 to 21 (40/100,000) in 2003 (p<.03). No cases were reported in individuals < 1-year. One individual was hospitalized. There were a greater number of individuals with HZ who had varicella (191) compared to those with who had a history of varicella vaccination (22) . The overall mean age of HZ cases were 10.4 years. In the vaccinated, the mean age of HZ was 4.77 years; whereas, in those with previous varicella infection, the mean age of HZ was 11.2 years. When vaccinated and unvaccinated individuals between 1-4 years were compared, the mean ages were comparable, 2.39 and 1.92 years for natural and vaccinated cases respectively.

CONCLUSION:
Our data show there has not been an increase in HZ incidence in children and adolescents in a highly vaccinated population.

LEARNING OBJECTIVES:

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