Background
Although the world made remarkable progress in reducing under-five mortality from 12.6 million deaths in 1990 to 5.4 million in 2017, it remains a serious public health problem [
1]. In 2017, an estimated 5.4 million children under the age of five died worldwide. This translates into 15,000 deaths per day. Sub-Saharan Africa (SSA) continues to be the region with the highest under-five mortality rate (76 deaths per 1000 live births in 2017) in the world [
1,
2]. According to the 2019 Ethiopian Mini Demographic and Health Survey (EMDHS) report, under-five mortality in Ethiopia was 55 deaths per 1000 live births [
3]. More than half of early childhood deaths are due to diseases that could be easily prevented or treated with simple and affordable interventions, such as administering vaccines [
2,
4].
Vaccination is one of the most cost-effective means of public health interventions to prevent deaths from childhood infectious diseases. Currently, vaccination prevents 2–3 million deaths annually. An additional 1.5 million deaths could be totally avoided through vaccination [
5]. In developing countries, about 16% of under-five deaths are attributed to vaccine-preventable diseases [
6]. In Ethiopia, vaccine-preventable diseases such as pneumonia and diarrheal disease are the leading causes of under-five mortality [
7]. Despite the benefits above-mentioned, approximately 19.4 million infants worldwide were not reached by immunization services in 2018. The total number of unvaccinated children, 60% lived in 10 countries: Angola, Brazil, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Nigeria, Pakistan, the Philippines, and Vietnam [
8]. According to the 2019 EMDHS report, only 43% of Ethiopian children aged 12–23 months were fully vaccinated [
3].
The World Health Organization (WHO) launched the Expanded Programme on Immunization (EPI) in 1974, intending to provide universal access to all relevant vaccines for all at risk [
9]. EPI in Ethiopia was started in 1980, with a plan to reach 100% coverage in 1990 [
10]. The Ethiopian government mobilized the volunteer Women’s Development Army or volunteers, health extension workers (HEWs), and health facilities to achieve universal immunization coverage [
7,
11]. likewise, the immunization coverage in Ethiopia increased from 14.3% in 2000 to 43% in 2019 [
3,
12]. To improve vaccination coverage by implementing different effective interventions, comprehensive nationwide evidence is vital. In Ethiopia, despite many fragmented studies that have been reported so far, a study representing the national and regional immunization coverage is lacking. The reasons mentioned above triggered us to conduct this comprehensive review to summarize the available evidence on routine immunization in Ethiopia. Thus, this review is intended to estimate the national coverage of childhood immunization in Ethiopia. Results obtained from this review will help health policymakers to design evidence-based public health responses.
Discussion
To the best of our knowledge, this systematic review and meta-analysis is the first of its kind to estimate the full vaccination coverage among children aged 12–23 months in Ethiopia. The overall pooled proportion of full vaccination coverage among children in Ethiopia was found to be 60% (95% CI: 50, 69%). This finding is in agreement with the findings of studies conducted in Kenya (57.7%) [
45], Malawi (51%) [
46], and Uganda (68%) [
47]. However, our finding is higher than the vaccine coverage proportions presented in the 2011 EDHS (24%), the 2016 EDHS (39%), and the 2019 EMDHS (43%) reports [
3,
23,
48]. The above differences could be elucidated by the fact that the demographic and health surveys were conducted in different segments of the country; which contained data from children live in rural and urban areas. However, in our meta-analysis only community based cross-sectional studies were included. Similarly, our estimate is also higher compared to reports from Nigeria (34.4%) [
49], India (39%) [
50], and Brazil (47%) [
51]. These discrepancies might be due to differences in data generating methods, and the level of government interventions and commitments.
On the other hand, our finding is much more lower than the WHO recommended level (≥ 90%) [
52]. This shortfall in reaching WHO’s 90% target could be due to common challenges facing the immunization program in Ethiopia, such as immunization service interruption due to supply shortages, limited outreach services in hard-to-reach communities, and EPI staff turnover [
53].
The subgroup analyses also showed that vaccination coverage across regions of Ethiopia was highly dispersed. The lowest coverage was observed in Afar Region (21%), while the highest coverage was observed in Amhara Region (73%). This regional variation is in line with the 2019 EMDHS report [
3]. This discrepancy could be explained by differences in the caregiver’s educational level as well as differences in socio-cultural and religious backgrounds.
Additionally, the pooled estimate of full vaccination coverage before 2015 was 48%, whereas the pooled estimate of full vaccination coverage after 2015 was 68%. From this finding, we can understand that the proportion of vaccine coverage among children has increased slightly in every consecutive year. This finding implies that the country has been implementing different strategies to improve childhood vaccination coverage. This finding is in parallel with the EDHS surveys conducted over time indicated that the vaccination coverage has increased from 14.4% in 2000 to 43% in 2019 [
3,
12]. This promising increase in the proportion of full vaccination coverage might be due to improvements in accessibility and provision of immunization services to the wider population. However, since the inclusion period is almost 20 years, children born in 2000 are now adults; therefore, their vaccination coverage may not represent the current childhood vaccination coverage.
Since this included community based cross-sectional studies, the findings can be generalized to the entire population of children aged 12–23 months in Ethiopia. However, our review has some limitations. Firstly, we were unable to find studies conducted in some regions of the country. Therefore, further community-based studies shall be done in regions such as Benishangul Gumuz, Dire-Dawa City Administration, Harari, and Gambella. Such that not having estimates for them might bias pooled coverage estimates. Since these regions were found far away from the central location of the country and presence of some insurrection, may contribute for lack of evidences for our estimate. Secondly, the current review considered only papers published in English language. At last, some biases might be introduced sine we used the NOS for quality assessment tool. In this tool, some domains were not univocal; and lacked comprehensive definition for each domain.
Conclusions
Our review suggested that six in every 10 children in Ethiopia were fully vaccinated. However, this finding is much lower than the WHO-recommended level (≥ 90%). In addition, vaccination coverage among children was highly varied across the regions of the country. Furthermore, in Ethiopia, the vaccine coverage among children has increased slightly in each consecutive year.
Therefore, a special attention should be given to improve the overall childhood vaccination coverage across the country.
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