The Changing Epidemiology of Pertussis In Georgia: An Analysis of Surveillance Data From 2005-2010

Background: During 2005-2010, pertussis in Georgia followed the national upward trend, although the disease remains significantly under-reported. In 2005, Georgia had the fewest number of reported pertussis cases and the lowest incidence rate among the 10 most-populated states. By 2009, the number of reported pertussis cases had nearly tripled, with a four-fold increase in the pertussis incidence rate.

Objectives: To characterize the epidemiology of pertussis in Georgia over the past six years

Methods: Demographics, type of laboratory diagnosis, clinical characteristics and complications from pertussis cases reported in Georgia during 2005-2010 were obtained from the State Electronic Notifiable Disease Surveillance System (SENDSS). A case was classified as probable or confirmed using the Centers for Disease Control and Prevention (CDC) and Council of State and Territorial Epidemiologists (CSTE) pertussis case definition.

Results: The overall pertussis incidence rate (cases per 100,000 population) in 2005 was 0.5 (n=79) compared to 2.3 in 2009 (n=230). In 2005, children ages 7-10 and adults accounted for 3.8% and 10.1% of reported cases, respectively. In 2009, reported cases children 7-10 increased to 21.7%, while pertussis cases among adults remained stable at 10.4%. Similarly, among cases, the frequency of signs, symptoms, complications, number of hospitalizations, immunization history and type of laboratory diagnostics also changed. One pertussis-related infant death occurred annually in Georgia between 2005 and 2009, with the exception of 2006. [2010 data is pending and will be included in the poster presentation]

Conclusions: In Georgia, the incidence of pertussis appears to be increasing among young children 7 to10 years of age. Pertussis remains under-recognized, under-diagnosed and under-reported in adults. To what degree the increase in pertussis cases reflects a true change in disease burden remains unclear. Increased awareness of pertussis, greater availability of laboratory tests, and improved reporting have likely contributed to this apparent increase in incidence.