Assessing Vaccine Coverage and Timeliness in Bamako, Mali after the Introduction of Rotavirus Vaccine: A Modified Immunization Cluster Survey.

Anna Roose,Uma Onwuchekwa,Samba Sow,Karen Kotloff,T Christopher Mast,Milagritos Tapia

doi:10.4269/ajtmh.21-0148

Abstract

ABSTRACT.Vaccine coverage and timeliness are critical metrics for evaluating the performance of immunization programs. Following the introduction of rotavirus vaccine in Bamako, Mali, we conducted two cluster surveys spaced approximately 1 year apart to evaluate these metrics among children 9 to 20 months of age. Using the child’s immunization card or the medical record at the center of administration, each selected child’s immunization status was determined at 9 and 12 months of age. Deviations from the WHO-recommended immunization schedule were described by the median delay and fraction of children receiving doses outside of recommended age ranges. Overall, 1,002 children were enrolled in the two surveys combined; 80.1% of children born 7 to 12 months after introduction (survey 1) received three doses of pentavalent rotavirus vaccine (ROTA3) by 9 months of age, which increased to 86.1% among children born 17 to 26 months after introduction (survey 2). Concomitantly, coverage with the third dose of diphtheria-pertussis-tetanus-containing vaccine (DPT3) by age 9 months was 86.5% (survey 1) and 88.9% (survey 2); by age 12 months, 61.3% and 72.4% of children, respectively, had received all scheduled immunizations. The median delay in ROTA3 and DPT3 administration were similar at about 3.4 weeks. Within 3 years of introduction, coverage of rotavirus vaccine among Bamako infants achieved coverage similar to DPT3 and is approaching the Global Vaccine Action Plan goal of 90% coverage by 2020. However, timeliness of coverage remains a concern.

Highlights

Since the introduction of the WHO’s Expanded Program for Immunization (EPI) in 1974 and the creation of Gavi, the Vaccine Alliance in 2000, the availability of immunizations to children in low- and middle-income countries has greatly improved.[1,2,3] significant global inequalities in vaccine coverage and access persist
The African region, where 45–50% vaccine-preventable morbidity and mortality occurs,[4] has the lowest coverage of core childhood immunizations of all WHO regions. In this region, estimated coverage for the third dose of diphtheria-pertussis-tetanus containing vaccine (DPT3) was only 72% in 2016.5 During the decade since WHO recommended introduction of rotavirus vaccine into all national immunization programs, only three-quarters of sub-Saharan African countries have followed suit, even though most diarrheal deaths occur in sub-Saharan Africa and most are attributable to rotavirus.[6,7,8]
A 2009 review of the timing of vaccine administration in 45 countries found that the median delay was 6.2 weeks for DPT3, and among West African nations, median coverage of DPT3

Summary

Introduction

Since the introduction of the WHO’s Expanded Program for Immunization (EPI) in 1974 and the creation of Gavi, the Vaccine Alliance in 2000, the availability of immunizations to children in low- and middle-income countries has greatly improved.[1,2,3] significant global inequalities in vaccine coverage and access persist. The African region, where 45–50% vaccine-preventable morbidity and mortality occurs,[4] has the lowest coverage of core childhood immunizations of all WHO regions. Factors such as interference from maternal transplacental antibody and immunological immaturity may prevent an effective immune response,[10,11,12] whereas delayed administration may leave a child vulnerable to infection during the ages where attack rates are high.[13,14] A 2009 review of the timing of vaccine administration in 45 countries found that the median delay was 6.2 weeks for DPT3, and among West African nations, median coverage of DPT3

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