Peer-reviewed article

Timeliness of routine vaccination among 24-35 months children in Urban Gambia.

Bakalilu Kijera, Alieu Sowe, Mary Bobb, Sarja Jarjusey, Lamin F Manjang et al. · 3 Apr 2026

Abstract

INTRODUCTION: Achieving the full benefits of immunization requires both high coverage and timely delivery of scheduled vaccines to provide maximum protection against specific infections. This study aimed to assess coverage and timeliness of routine childhood vaccinations among children in urban areas of The Gambia. METHODS: A cross-sectional quantitative study was conducted among children in Western Region 1 (urban Gambia). A multi-stage cluster sampling method was employed, based on the WHO 30 X 7 cluster survey approach. Vaccination data were collected for children aged 24-35 months. Vaccinations were categorized as 'early', 'timely', or 'delayed' based on accepted vaccination windows as defined by the Gambia Expanded Program on Immunization (EPI). Data were analyzed using Kaplan-Meier curves to describe time to vaccination events. RESULTS: Among the 355 children surveyed, 88.7% (315/355) had Infant Welfare Cards. Vaccines administered during the first year of life (0-11 months) had higher coverage than those given in the second year (12-23 months). The first dose of the pentavalent vaccine (Penta 1) had the highest timeliness at 75.4%, whereas the Oral Polio Vaccine booster (OPVb) recorded the least timeliness at 29.7%. The proportion of doses administered too early ranged from 4.1% to 11.5% for the first dose of measles-containing vaccine (MCV1) and OPVb, respectively. The highest proportion of delays was for the birth dose of the Hepatitis B vaccine (68.2%)-the proportion of children receiving the Pentavalent vaccine on time or early decreased with subsequent doses. CONCLUSION: Timeliness has improved compared with previous studies but remains below the target. However, additional efforts are required to drive further improvement, especially for the Hepatitis B vaccine and vaccines administered in the second year of life, to strengthen the control of relevant Vaccine Preventable Diseases (VPDs). Health workers should regularly conduct defaulter tracing to reach every child, to improve coverage and timeliness. Also, strengthen interpersonal communication on the importance of timely vaccination.