Invasive Neonatal Group-B Streptococcus (GBS) Disease in Wisconsin, 2002-2008 2008 Hanne Nissen Bjørnsen RN, MS MPH Candidate 2010 University of Wisconsin - Madison May 7 th 2010
Streptococcus agalactiae (GBS) Leading cause of neonatal morbidity and mortality in United States o Most common cause of sepsis and meningitis in newborns 10 30 % of pregnant women carry the bacteria at any time Frequent cause of newborn pneumonia o More common than rubella, congenital syphilis, and spina bifida Early onset disease (EOD): 0-6 days Late onset disease (LOD): 7-90 days
Streptococcus agalactiae(gbs) Transmission o During labor o After labor Switch from risk-based screening to universal screening in 2002 All pregnant women should be screened for GBS at 35-37 weeks gestation o GBS + are treated with antibiotics during labor
Wisconsin GBS surveillance Became reportable under Wisconsin state law in April 2001 o Wisconsin Statute 252.05 and 252.21, Communicable Diseases, and Wisconsin Administrative Rule 145.04(d) and 145.06, Control of Communicable Diseases
Why perform GBS surveillance? Prevent morbidity and mortality in newborn infants Determine o Prevalence o Incidence o Distribution of disease in the population Establish baseline data o Recognize deviations Evaluate impact of interventions o Screening, educational programs, future vaccines
Methods Evaluated surveillance data from Wisconsin for 2002-2008 o Disease incidence rates o Mortality rates o Overall and by race, gender
Methods Case finding and case definition Case finding o Division of Public Health report forms o State Laboratory report forms o Electronic disease surveillance records o Vital Statistics records o For cases with incomplete data Case definition o Wisconsin resident 0-90 days old at time of disease onset o Laboratory-confirmed GBS-positive specimen collected January 1, 2002 December 31, 2008
Methods Data Analysis Rates calculated in Excel olive birth data from Wisconsin vital statistics for denominators Statistical significance of rates ochi-square and Poisson regression
Results 212 culture-confirmed cases in Wisconsin Average annual incidence o 0.43 cases per 1000 live births Average annual mortality rate o 0.04 deaths per 1000 live births o Average 2.71 infant deaths per year o Case fatality ratio 9.4% No overall trends Disparities in rates by race and by gender
Results Rates by Gender in Wisconsin Females - 45.8% of cases Males - 54.2% of cases Case-fatality rate for females was more than four times that for males o Females 15.5% o Males 3.5% Chi-square: p = 0.002
Comparison with National Data Compared EOD disparity data with national data Active Bacterial Core (ABC) o CDC s active surveillance system for GBS o 10 sites across United States o 41 million people Healthy People 2010 objective o Decrease the incidence of invasive early-onset group B streptococcal disease to 0.5 cases per 1,000 live births
Discussion of Disparities Possible reasons for higher rates in blacks o Higher colonization rates o Pre-term delivery more common, increases risk for early and late-onset GBS o Diabetes associated with GBS Gender
Limitations Wisconsin enhanced passive surveillance ABC active surveillance
Summary and Recommendation Disparities in GBS-related morbidity and mortality persist in Wisconsin Despite overall reduction in infant mortality Target public health target funding and educational activities towards groups at increased risk for GBS disease
Acknowledgments University of Wisconsin, MPH Program Susan Zahner Dr.PH, RN, M.P.H., Barb Duerst, Associate Director MPH Program Wisconsin Division of Public Health Susann Ahrabi-Fard, M.S., Richard Heffernan, M.P.H., Amy Karon, D.V.M., M.P.H Centers for Disease Control and Prevention Epidemiology & Laboratory Capacity grant Wisconsin State Laboratory of Hygiene Bacteriology/PFGE laboratory Wisconsin health departments, laboratories and Infection Preventionists