title: The California Pertussis Epidemic 2010: A Review of 986 Pediatric Case Reports From San Diego County.
abstract: BACKGROUND
  The California Department of Public Health (CDPH) declared a pertussis epidemic on 23 June 2010. More cases were reported in 2010 (9146) than in any year since 1947. We describe the characteristics of pertussis epidemiology and disease from 986 reported cases in children in San Diego County (population 3.2 million).
  
  
  METHODS
  Descriptive statistics were abstracted from CDPH pertussis case report forms that were completed by public health nurses investigating reports of positive laboratory results for pertussis and reports of illnesses compatible with pertussis.
  
  
  RESULTS
  Of 1144 reported adult and pediatric cases, 753 (66%) were confirmed and 391 were probable/suspect. Children aged <19 years comprised 86% of all reported cases in San Diego County; of these, 22% were aged 11-18 years, 29% were aged 6-10 years, 27% were aged 1-5 years, and 22% were aged <1 year (with 70% aged <6 months). Case rates were highest in infants aged <6 months (651 per 100 000 population). Of those aged >1 year, the highest attack rates were in preschool children aged 1-5 years (114 per 100 000) and elementary school children aged 6-10 years (141 per 100 000). Of 51 children hospitalized, 82% were aged <6 months; 2 deaths occurred in these young infants. Paroxysmal cough was noted in over 70% of children in all age groups; post-tussive vomiting occurred in 36% (aged 11-18 years) to 57% (aged <6 months) of children.
  
  
  CONCLUSIONS
  Pertussis vaccine efficacy may decrease more rapidly than previously believed, facilitating spread of pertussis in elementary school-aged children. The highest case rates and the only mortality occurred in infants aged <6 months.
authors.affiliation: Department of Pediatrics, University of California San Diego School of Medicine.
authors.forename: M H
authors.initials: MH
authors.lastname: Chan
authors.affiliation: Department of Pediatrics, University of California San Diego School of Medicine.
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.affiliation: County of San Diego Health and Human Services Agency, Public Health Services Administration.
authors.forename: D
authors.initials: D
authors.lastname: Sidelinger
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: L
authors.initials: L
authors.lastname: Bethel
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: J
authors.initials: J
authors.lastname: Yen
authors.affiliation: Department of Pediatrics, University of California San Diego School of Medicine.
authors.forename: A
authors.initials: A
authors.lastname: Inveiss
authors.affiliation: Department of Pediatrics, University of California San Diego School of Medicine County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch Rady Children's Hospital San Diego, California.
authors.forename: M H
authors.initials: MH
authors.lastname: Sawyer
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: K
authors.initials: K
authors.lastname: Waters-Montijo
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: J M
authors.initials: JM
authors.lastname: Johnson
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: L
authors.initials: L
authors.lastname: Hicks
authors.affiliation: County of San Diego Health and Human Services Agency, Public Health Services Administration.
authors.forename: E C
authors.initials: EC
authors.lastname: McDonald
authors.affiliation: County of San Diego Health and Human Services, Epidemiology and Immunization Services Branch.
authors.forename: M M
authors.initials: MM
authors.lastname: Ginsberg
authors.affiliation: Department of Pediatrics, University of California San Diego School of Medicine Rady Children's Hospital San Diego, California jbradley@rchsd.org.
authors.forename: J S
authors.initials: JS
authors.lastname: Bradley