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Risk factors associated with typhoid fever in children aged 2–16 years in Karachi, Pakistan

  • M. I. KHAN (a1), R. L. OCHIAI (a1), S. B. SOOFI (a2), L. VON-SEIDLEIN (a3), M. J. KHAN (a2), S. M. SAHITO (a2), M. A. HABIB (a2), M. K. PURI (a1), J. K. PARK (a1), Y. A. YOU (a1), M. ALI (a1), S. Q. NIZAMI (a2), C. J. ACOSTA (a1), R. BRADLEY-SACK (a4), J. D. CLEMENS (a1) and Z. A. BHUTTA (a2)...

We analysed the data from the control group in a typhoid vaccine trial in Karachi to assess the differences in individual-, household- and cluster-level characteristics for developing typhoid fever. The annual incidence of typhoid in children aged 2–16 years in the control arm of the vaccine trial was 151/100 000 population. After adjustment, the risk of typhoid was lower with increasing age [risk ratio (RR) 0·89, 95% confidence interval (CI) 0·83–0·95], was higher with an increase in population density (RR 1·13, 95% CI 1·05–1·21) and was lower in the households using a safe drinking-water source (RR 0·63, 95% CI 0·41–0·99). Typhoid fever affects younger children living in areas of high population density and lack of access to safe water in Pakistan. A combination of environmental and biological interventions is required to prevent the continued epidemiological and economic impact of typhoid fever in high-risk areas of Pakistan.

Corresponding author
*Author for correspondence: Professor Z. A. Bhutta, Husein Lalji Dewraj Professor and Chair, Division of Women & Child Health, The Aga Khan University, PO Box 3500, Stadium Road, Karachi 74800, Pakistan. (Email:
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Epidemiology & Infection
  • ISSN: 0950-2688
  • EISSN: 1469-4409
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