Effect of educating mothers on completion of three doses of DPT and hepatitis B vaccines among their infants in Karachi, Pakistan- a randomized controlled trail

Date of Award


Document Type


Degree Name

Master of Science in Epidemiology & Biostatistics (MSc Epidemiology & Biostats)


Community Health Sciences


Introduction: An estimated 60,000 Pakistani children die each year from vaccine preventable diseases. Immunization rates are low with less than 60% of infants fully immunized. The high infant mortality (89 per thousand live births) and morbidity of Pakistani children is partly attributable to low immunization coverage. Objectives: To evaluate impact of a low-cost immunization promotion educational intervention for mothers living in low-income communities of Karachi on: (1) Completion of DPT3-Hepatitis B vaccine (i.e. 3 doses of Diphtheria, Pertussis, Tetanus and Hepatitis B vaccines) immunization rates in their infants. (2) Retention of immunization cards 4 months after the educational intervention. Methods: Design: Multi-site community-based, randomized controlled trial evaluating impact of immunization promotion educational interventions compared to routine health promotion messages to mothers on DPT-3-Hepatitis B immunization completion rates in their infants. Settings and Participants: This study was carried out in five low-income communities of Karachi during August 2008-March 2009. Participants were mothers of infants aged 0 to 42 days identified through pre-existing pregnant women and newborn surveillance databases in these areas. Of 366 mother-infant pairs enrolled, 183 were randomly assigned to intervention group and 183 to control group, using computer generated randomization sequences. Type of Intervention: The intervention consisted of educational messages to mothers using three simple laminated pictorial cards. The messages were given by trained community health workers (CHWs) at each participant's home. The first message emphasized how vaccines save children's lives. The second message provided logistic information about the address and location of local vaccination centers. The third message highlighted the significance of retaining immunization cards. A copy of pictorial messages was left with the mother. The control group received verbal health promotion messages about hand washing, breast-feeding, clean water, benefits of using ORS, care-seeking for illness, importance of antenatal check-ups and also some general information on vaccines by trained CHWs. The length of each educational session in both groups was 10-15 minutes. Primary outcome: Infants receiving all three doses of DPT/Hepatitis B vaccines (assessed through vaccination cards) were considered as "DPT-3/Hepatitis B completed" and infants missing any dose of DPT-3/Hepatitis B or who had lost their vaccination cards were termed "DPT-3/Hepatitis B not completed" Secondary outcome: Rate of retention of immunization cards, 4 months after enrollment in the trial. Results: Baseline characteristics among the two groups were similar. At the 4 month assessment, among 179 mother-infant pairs in the intervention group, 129 (72.1%) had received all 3 doses of DPT3/Hepatitis B vaccine, whereas in the control group 92/178 (51.7%) had received all 3 doses (RR= 1.39, 95% C1=1.07-1.82). In the intervention group, 145 (81%) infants retained vaccination cards compared to 123 (69.1%) infants in the control group (RR= 1.17, 95% CI=1.04-1.32). Multivariable analyses revealed that parental knowledge about impact of vaccines on child's health, education of mother, construction material of house, and living in rental housing was associated with DPT-3/Hepatitis B vaccine completion rates when intervention was controlled for (P<0.001). The adjusted odds ratio for DPT-3/Hepatitis B vaccine completion rates was 2.59 (95% CI=1.59-4.22) when controlling for the above mentioned covariates. Conclusion: A simple educational intervention designed for low-literate populations, increased DPT-3/ Hepatitis B vaccine completion rates by 20 percentage points and retention of vaccination cards by families 12 percentage points. These findings have important implications for improving routine immunization rates in Pakistan.

This document is available in the relevant AKU library