title: Epidemiology of Pertussis Among Young Pakistani Infants: A Community-Based Prospective Surveillance Study.
abstract: BACKGROUND
  Pertussis remains a cause of morbidity and mortality among young infants. There are limited data on the pertussis disease burden in this age group from low- and lower-middle-income countries, including in South Asia.
  
  
  METHODS
  We conducted an active community-based surveillance study from February 2015 to April 2016 among 2 cohorts of young infants in 4 low-income settlements in Karachi, Pakistan. Infants were enrolled either at birth (closed cohort) or at ages up to 10 weeks (open cohort) and followed until 18 weeks of age. Nasopharyngeal swab specimens were obtained from infants who met a standardized syndromic case definition and tested for Bordetella pertussis using real-time polymerase chain reaction. We determined the incidence of pertussis using a protocol-defined case definition, as well as the US Centers for Disease Control and Prevention (CDC) definitions for confirmed and probable pertussis.
  
  
  RESULTS
  Of 2021 infants enrolled into the study, 8 infants met the protocol-defined pertussis case definition, for an incidence of 3.96 (95% confidence interval [CI], 1.84-7.50) cases per 1000 infants. Seven of the pertussis cases met the CDC pertussis case definition (5 confirmed, 2 probable), for incidences of CDC-defined confirmed pertussis of 2.47 (95% CI, .90-5.48) cases per 1000 infants, and probable pertussis of 0.99 (95% CI, .17-3.27) cases per 1000 infants. Three of the pertussis cases were severe according to the Modified Preziosi Scale score.
  
  
  CONCLUSIONS
  In one of the first prospective surveillance studies of infant pertussis in a developing country, we identified a moderate burden of pertussis disease in early infancy in Pakistan.
authors.affiliation: Department of Global Health.|Department of Epidemiology.|Department of Pediatrics.|Department of Emory Vaccine Center, Emory University, Atlanta, Georgia.
authors.forename: Saad B
authors.initials: SB
authors.lastname: Omer
authors.affiliation: Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
authors.forename: A Momin
authors.initials: AM
authors.lastname: Kazi
authors.affiliation: Department of Epidemiology.|Department of Emory Vaccine Center, Emory University, Atlanta, Georgia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bednarczyk
authors.affiliation: Department of Global Health.
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Allen
authors.affiliation: Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention.
authors.forename: Conrad P
authors.initials: CP
authors.lastname: Quinn
authors.affiliation: Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
authors.forename: Fatima
authors.initials: F
authors.lastname: Aziz
authors.affiliation: Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
authors.forename: Khurram
authors.initials: K
authors.lastname: Sial
authors.affiliation: Division of Infectious Diseases, Emory University, Atlanta, Georgia.
authors.forename: Varun K
authors.initials: VK
authors.lastname: Phadke
authors.affiliation: Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Tondella
authors.affiliation: Meningitis and Vaccine Preventable Diseases Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention.
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Williams
authors.affiliation: Department of Emory Vaccine Center, Emory University, Atlanta, Georgia.|Division of Infectious Diseases, Emory University, Atlanta, Georgia.
authors.forename: Walter A
authors.initials: WA
authors.lastname: Orenstein
authors.affiliation: Department of Paediatrics and Child Health, Aga Khan University, Karachi, Pakistan.
authors.forename: S Asad
authors.initials: SA
authors.lastname: Ali
mesh_terms: D001886:Bordetella pertussis; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010154:Pakistan / Q000453:epidemiology; D011159:Population Surveillance; D011446:Prospective Studies; D012621:Seasons; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D014917:Whooping Cough / Q000175:diagnosis / Q000453:epidemiology*
keywords: Pakistan; Tdap; maternal vaccine; pertussis; surveillance