Routine Immunization Status and Factors Associated with Immunization Coverage among Children Aged 12–23 Months in Tanzania

Immunization has saved millions of lives globally from vaccine-preventable diseases. Childhood immunization is an effective public health strategy for decreasing morbidity and mortality among children in developing countries. Tanzania has one of the highest rates of coverage of routine child immunization among sub-Saharan African countries. However, obstacles to universal immunization still exist, particularly in rural areas of the country. Assessing routine immunization coverage is essential to inform vaccine policies and program implementation. This study aimed to assess routine immunization status and factors associated with its coverage among children aged 12-23 months. We conducted a cross-sectional, quantitative household survey in 31 regions with caretakers of children in Tanzania, where a total of 4,560 households were visited. Nationally, 85.5% of children aged 12-23 months had completed the full recommended course of vaccines. Overall, 14.5% of children aged 12-23 months did not complete routine immunization schedules in 2019. We found that factors associated with immunization coverage included having one to six family members, higher household wealth, the family's head engaging in subsistence farming, caretakers' age, children's age, educational level, children with clinic cards, and children receiving the diphtheria, pertussis, tetanus-3 vaccine. The country is about to reach the vaccination coverage target set by the WHO and the United Nations Children Fund. Improving existing vaccination coverage and optimizing the use of recommended interventions are required. We strongly advise using the periodic micro-planning tool and satellite image technology, particularly in areas where immunization coverage is less than 80%.