KEYWORDS:
Varicella, Susceptibility, Vaccine, Adolescent, Retrospective Survey

BACKGROUND:
Population-based active surveillance for varicella in the Antelope Valley, California, a geographically distinct community with a population of 327,000, has shown a 72% decline in varicella incidence since licensure of varicella vaccine in 1995 and a vaccine coverage rate in 2001 of 72% among children aged 12 to 23 months. With decreasing opportunity for community exposure to varicella, a concern existed that children who escape disease and are not vaccinated might remain susceptible to varicella as adolescents, when the complications of varicella are more severe.

OBJECTIVE(S):
To determine the susceptibility to varicella among adolescents aged 10 to 14 years old.

METHOD(S):
We distributed a self-administered questionnaire to parents through school enrollment packages to all thirteen public middle (7th and 8th grade) school students. The questionnaire collected information on demographics, history of varicella disease, vaccination status, and duration of Antelope Valley residency.

RESULT(S):
We received 4,216 responses, for an overall response rate of 35%. Although the response rates varied by school, ranging from 12%-94%, the overall racial/ethnic distribution of respondents closely reflected that reported by California Basic Educational Demographics Survey (CBEDS) for the surveyed schools, 50% were white, 31% Hispanic, 14% African American, and 5% Asian/other. 3,627 (86%) of the respondents reported that their children had a positive history of varicella disease, and 266 (6.3%) reported that their children received varicella vaccine. Thus 7.7% (95% CI 6.9- 8.5) were susceptible or had unknown susceptibility.

CONCLUSIONS(S):
At this time, adolescents should be queried as to their varicella susceptibility during health care visits for any reason, and those with a negative or unknown varicella history or vaccination status should be offered vaccine.

LEARNING OBJECTIVES: