Affiliations: Division of Infectious Diseases, Illinois Department
of Public Health, Chicago, IL 60607-7127, USA | Division of Infectious Diseases, Illinois Department
of Public Health, Springfield, IL 60607-7127, USA | Division of Epidemiology and Biostatistics, University
of Illinois at Chicago, School of Public Health, Chicago, IL 60607-7127,
USA
Note: [] Correspondence: Dr. Stephanie M. Borchardt, Fargo Veterans
Administration Medical Center, 2101 Elm Street N (151), Fargo, ND 58102, USA.
Tel.: +1 701 239 3700 Ext. 3348; Fax: +1 701 237 2652; E-mail:
stephanie.borchardt@va.gov
Abstract: Varicella vaccine was licensed in the United States in March 1995.
During 1995 to 2000, active surveillance sites observed a 71% to 84%
decrease in cases of varicella infection. We describe an evaluation of the
passive varicella surveillance system in Illinois including trends in the
incidence of varicella and the impact of a school-entry vaccine requirement.
Varicella surveillance data and varicella-specific hospital discharge data
collected by the Illinois Department of Public Health (IDPH) during January
1995 through December 2005 were reviewed and summarized. IDPH received 29,189
aggregate reports representing 138,177 cases of varicella infection and 136
individual case reports. Incidence of varicella infection declined 95% from
2.0 cases per 1000 population in 1995 to 0.1 cases per 1000 population in 2005.
Hospital discharge data also demonstrated a notable decline (78%). IDPH
policy requiring vaccination of children ⩾ 2 years of age enrolled in
child care facilities or school-operated programs at or below the kindergarten
level was temporally associated with a decline from 10,805 cases in 2002 to
3,829 cases in 2003 (65%). Widespread use of the varicella vaccine has
resulted in a marked decline in cases of varicella infection, thereby
decreasing the burden of reporting and increasing the feasibility of case-based
reporting.
