Lessons and Implications from a Mass Immunization Campaign in Squatter Settlements of Karachi, Pakistan: An Experience from a Cluster-randomized Double-blinded Vaccine Trial [NCT00125047]

Authors

Mohammad Imran Khan, Aga Khan University, Karachi, Pakistan
Rion Leon Ochiai, International Vaccine Institute, Seoul, Korea
Hasan Bin Hamza, Aga Khan University, Karachi, Pakistan
Shah Muhammad Sahito, Aga Khan University, Karachi, Pakistan
Muhammad Atif Habib, Aga Khan University, Karachi, Pakistan
Sajid Bashir Soofi, Aga Khan University, Karachi, Pakistan
Naveed Sarwar Bhutto, Aga Khan University, Karachi, Pakistan
Shahid Rasool, Aga Khan University, Karachi, Pakistan
Mahesh K. Puri, International Vaccine Institute, Seoul, Korea
Mohammad Ali, International Vaccine Institute, Seoul, Korea
Shafi Mohammad Wasan, Aga Khan University, Karachi, Pakistan
Mohammad Jawed Khan, Aga Khan University, Karachi, Pakistan
Remon Abu-Elyazeed, US NAMRU 3, Cairo, Egypt
Bernard Ivanoff, World Health Organization
Claudia M. Galindo, International Vaccine Institute, Seoul, Korea
Tikki Pang, World Health Organization
Allan Donner, University of Western OntarioFollow
Lorenz von Seidlein, International Vaccine Institute, Seoul, Korea
Camilo J. Acosta, International Vaccine Institute, Seoul, Korea
John D. Clemens, International Vaccine Institute, Seoul, Korea
Shaikh Qamaruddin Nizami, Aga Khan University, Karachi, Pakistan
Zulfiqar A. Bhutta, Aga Khan University, Karachi, Pakistan

Document Type

Article

Publication Date

5-25-2006

Journal

Trials

Volume

7

Issue

17

Abstract

Objective: To determine the safety and logistic feasibility of a mass immunization strategy outside the local immunization program in the pediatric population of urban squatter settlements in Karachi, Pakistan.

Methods: A cluster-randomized double blind preventive trial was launched in August 2003 in 60 geographic clusters covering 21,059 children ages 2 to 16 years. After consent was obtained from parents or guardians, eligible children were immunized parenterally at vaccination posts in each cluster with Vi polysaccharide or hepatitis A vaccine. Safety, logistics, and standards were monitored and documented.

Results: The vaccine coverage of the population was 74% and was higher in those under age 10 years. No life-threatening serious adverse events were reported. Adverse events occurred in less than 1% of all vaccine recipients and the main reactions reported were fever and local pain. The proportion of adverse events in Vi polysaccharide and hepatitis A recipients will not be known until the end of the trial when the code is broken. Throughout the vaccination campaign safe injection practices were maintained and the cold chain was not interrupted. Mass vaccination in slums had good acceptance. Because populations in such areas are highly mobile, settlement conditions could affect coverage. Systemic reactions were uncommon and local reactions were mild and transient. Close community involvement was pivotal for information dissemination and immunization coverage.

Conclusion: This vaccine strategy described together with other information that will soon be available in the area (cost/effectiveness, vaccine delivery costs, etc) will make typhoid fever control become a reality in the near future.

Notes

Published in: Trials, 2006, 7:17. doi: 10.1186/1745-6215-7-17