Learning Objectives for this Presentation:
By the end of the presentation participants will be able to describe the epidemiology of pertussis in Ohio.

Background:
In 2003 there were over 11,000 cases of pertussis reported nationally; the highest number reported in 40 years. Approximately 40 percent of cases were adolescents (aged 10-19 years). Since 1997, the reported incidence of pertussis in Ohio has increased – more than doubling from 2003 to 2004. The incidence of pertussis among adolescents has also been steadily increasing since 2001. ACIP approved a booster dose of pertussis containing vaccine targeting children eleven years or older in an effort to decrease waning immunity.

Objectives:
Evaluate and characterize the distribution of pertussis cases in Ohio using GIS-based analysis.

Methods:
To understand the increase in pertussis cases among the general population and adolescents in Ohio, we analyzed data reported to the Ohio Department of Health (ODH) utilizing geographical information systems software (ArcGIS) and other methods. We also illustrated the epidemiologic characteristics of the incidence data using descriptive statistics.

Results:
The number of reported cases of pertussis increased from 328 in 2003 to 766 in 2004. Cases of pertussis reported among 10-19 year olds increased from 83 (24%) in 2001 to 287 (38%) in 2004. Of those 10-19 year olds who had pertussis in 2004, 62% were vaccinated with 5 doses of pertussis containing vaccine; 22% received a complete series of pertussis vaccine 8 years prior to infection. The geographic distribution of pertussis cases in Ohio was concentrated in certain major metropolitan areas.

Conclusions:
The apparent increase in pertussis may be the result of improved surveillance and increased reporting. The increase in the adolescent group upon stratification by time from vaccination to onset lends argument to a waning immunity given the evidence of the time after vaccination to disease onset in this age group.