Uptake and determinants of routine immunization among vulnerable children and adolescents in sub-Saharan Africa: A scoping review

Background

Despite notable improvements in coverage of immunization services in sub-Saharan Africa (SSA) over recent decades, there are marked inequities across populations. We undertook a scoping review to study the uptake and determinants of routine immunization (RI). This is the health system component that regularly delivers vaccination services to eligible populations as set out in national immunization schedules among vulnerable children and adolescents in sub-Saharan Africa.

Methods

We adopted the population-concept-context format to address the 2 research questions. The population was vulnerable children and adolescents from birth to 18 years from 2010 to 2020. The context was sub-Saharan Africa. An electronic search was conducted in PubMed, SCOPUS and African Journals Online, following which the selected studies were entered into a data extraction tool. Estimates of immunization uptake as well as quantitative and qualitative synthesis of demand and supply determinants of immunization were carried out.

Results

Out of the 6040 studies screened, 68 articles were finally selected.

Nineteen of these focused on older children and adolescents (9–18 years).

RI uptake ranged from 1/201 (0.01 %; 95 % CI:0.01–0.03) to 205/216 (95 %; 95 % CI:0.92–0.97). Demand-related factors that were positively correlated with RI uptake were non-Muslim religion (aOR:1.56,95 % CI:1.11–2.17), high caregiver vaccination knowledge (aOR:3.30,95 % CI:0.26–3.56), high household socio-economic status (aOR:1.25,95 % CI:1.04–1.49) and short distance from health facility (aOR:1.63,95 % CI:1.10–2.39). Attendance of less than 4 antenatal visits (aOR:0.47,95 %CI:0.32–0.67) and Somali ethnicity (aOR:0.41,95 %CI:0.19–0.91) were negatively associated with RI uptake. Only 3 quantitative studies examined supply determinants of immunization uptake. Conducive health facility attributes were positively correlated with RI uptake (aOR:2.21,95 % CI:1.22–3.98) while the cost of obtaining vaccination (aOR:1.01,95 % CI:0.63–1.60) and health worker shortage (aOR:0.33,95 % CI:0.02–0.13) were negatively correlated.

Conclusion

RI uptake among vulnerable sub-populations of children and adolescents varies widely. There is a paucity of studies on supply-side determinants of routine immunization uptake and also among adolescents.