Learning Objectives for this Presentation:
By the end of the presentation participants will be able to:
1. Describe the varicella zoster virus (VZV) seroprevalence among U.S. Army recruits.
2. Discuss whether VZV seroprevalence supports changes in Army recruit screening and vaccination policies.

Background:
In 1999, the Advisory Committee on Immunization Practices updated varicella vaccination recommendations for child care, school entry requirements, and adolescents and adults at high risk. In 2003 Ryan et. al. reported 93% seroprevalence for U.S. Navy recruits. The U.S. Army screens recruits for VZV antibodies and vaccinates those who are seronegative.

Objectives:
To describe VZV seroprevalence among U.S. Army recruits and determine if VZV seroprevalence supports changes in U.S. Army recruit screening and vaccination policies.

Methods:
VZV seroprevalence data were collected for new enlisted Army recruits (April 2006 to June 2007) and linked to demographic data from the Defense Medical Surveillance System. Seroprevalence is yes (positive) or no (negative or equivocal). Independent variables include age, race, gender, training site, marriage status, rank, and home state. Analysis was accomplished using multivariable categorical logistic regression.

Results:
Sample included 92,456 records. Mean age was 21.3 ±4.8, 82.3% male, and 70.6% white. Home state regions were South (42.7%), Midwest (28.2%), Northeast (14.0%), West (12.7%), non-U.S. (2.5%). VZV seroprevalence was 94.4%. Recruits from South (OR 1.15) and Midwest (OR 1.26) regions were more likely seropositive compared to West region. Northeast region was similar to the West, while non-U.S. state recruits were more likely seronegative (OR 2.28) compared to West. Older recruits (20-22, OR 1.20), (23-25, OR 1.27), (≥26, OR 1.20) were more likely seropositive compared to 17-19 year olds.

Conclusions:
Provides VZV seroprevalence of a large diverse sample entering U.S. Army. High VZV seroprevalence across geographical regions and age groups combined with corresponding herd effect may support changes in U.S. Army recruit serologic testing and vaccination policies.