Epidemiology of Pertussis Among Young Pakistani Infants: A Community-Based Prospective Surveillance Study.

• Authors: Saad Omer, Emory University; A. Momin Kazi, Aga Khan University; Robert Bednarczyk, Emory University; Kristen E. Allen, Emory University; Conrad P. Quinn, Centers for Disease Control and Prevention; Fatima Aziz, Aga Khan University; Khurram Sial, Aga Khan University; Varun K. Phadke, Emory University; Maria L. Tondella, Centers for Disease Control and Prevention; Margaret M. Williams, Centers for Disease Control and Prevention; Walter Orenstein, Emory University; S. Asad Ali, Aga Khan University
• Journal Title: Clinical Infectious Diseases
• Volume: Volume 63, Number suppl 4
• Publisher: Oxford University Press (OUP): Policy A1 - Oxford Open Option C | 2016-12-01, Pages S148-S153
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1093/cid/ciw561
• Subjects: Health Sciences, Epidemiology; Health Sciences, Public Health
• Keywords: Pakistan; Tdap; maternal vaccine; pertussis; surveillance

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.