616. The California Pertussis Epidemic: Pediatric Disease in San Diego County 2010
Session: Poster Abstract Session: Outbreak Investigation
Friday, October 21, 2011
Room: Poster Hall B1
  • 616_RobinMorrison(2).pdf (80.7 kB)
  • Background: The California (CA) Department of Public Health (CDPH) declared pertussis epidemic on June 23, 2010. More cases were reported in CA in 2010 (8383) than in any year since 1947. Based on a CDPH Pertussis Case Report Form (CRF), we describe characteristics of pertussis epidemiology and disease in 986 children in San Diego County (pop 3.2 million)

    Methods: Descriptive statistics on age and ethnicity, information on contacts, hospitalization, clinical disease and outcomes were abstracted from CDPH pertussis CRFs completed for each child by public health nurse investigation following report of a positive laboratory result, or report of illness compatible with pertussis.  

    Results: Of 986 reported cases in children 18 years and younger, 664 (67%) were confirmed, 322 were probable/suspect.   22% were 11-18 years, 29% 6-10 years, 27% 1-5 years, and 22% under 1 year (with 70% of those under 1 year, being under 6 months).  Age-specific case rates were highest in infants under 6 months (651/100K population).  Of those over one year, the highest attack rates were in preschool aged children 1-5 years (115/100K) and elementary school-aged children 6-10 years (142/100K).  By history, exposures occurred primarily in the home (59% of all cases), or at school (36%), with only 7% linked to daycare.  Of cases over 6 months, 90-95% had at least one dose of vaccine, with 55 families (6% of all cases) citing personal belief exemption for lack of immunization.  Of 51 children hospitalized, 82% were under 6 months; 2 deaths occurred in these young infants.  Of those under 6 months, 53%% were Hispanic.  Apnea was noted in 26% of infants under 6 months.  Paroxysmal cough was noted in over 70% of children in all age groups; post-tussive vomiting occurred in 36% (11-18 years) to 57% (under 6 mos) of children.

    Conclusion: Reasons for widespread pertussis in CA are unknown.  These data represent cases identified by passive reporting, and may not be complete.  Pertussis vaccine efficacy, known to be imperfect, may be less efficacious for the five years following immunization than previously believed, with high attack rates noted in elementary school-aged children.  The highest case rates and the only mortality were seen in infants under 6 months of age, who are not fully immunized.

    Subject Category: P. Pediatric and perinatal infections

    Marilynn Chan1, Dean Sidelinger, MD, MSEd2, Linda Bethel, MPH, BSN3, Jessica Yen, MPH4, Lawrence Ma1, Alda Inveiss1, Mark H. Sawyer, MD5 and John Bradley, MD, FIDSA6, (1)University of California, San Diego, San Diego, CA, (2)County of San Diego, Health and Human Services Agency, San Diego, CA, (3)Epidemiology and Immunization Services Branch, County of San Diego, Health and Human Services Agency , San Diego, CA, (4)Epidemiology and Immunization Services Branch, County of San Diego, Health and Human Services Agency, San Diego, CA, (5)University of California, San Diego, CA, (6)Pediatrics, University of California, San Diego, San Diego, CA


    M. Chan, None

    D. Sidelinger, None

    L. Bethel, None

    J. Yen, None

    L. Ma, None

    A. Inveiss, None

    M. H. Sawyer, None

    J. Bradley, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.