Ethiopia was committed to improve the access and continuum of vaccination to achieve full vaccination via designing health policies and strategies, such as the construction of health posts, training and deployment of health extension workers. The country has also made great gains in decreasing childhood and under-five mortality by two-thirds since 1990 and meeting its Millennium Development Goal target [24]. However, attaining the Sustainable Development Goal for reducing under-5 mortality from 59 deaths in 2015 [25] to 25 deaths per 1000 live births in 2030 [26] will require improved child health services through ensuring the access and continuum of childhood vaccination services. Despite access to childhood vaccination in the country, many children do not receive the vaccines.
As a result,25.1% (95%CI: 21.80, 28.30) of the children were fully vaccinated that does not lead in achieving the 2020 Health Sector Transformation Plan (HSTP). This finding was consistent with the 2011 EDHS report (24%) [9] and the Kenyan (22.6%) [27]. However, it was lower than those of studies done in Togo, Nigeria (63.7%) [28], Kwahu Afram Plains, Ghana (81.3%) [29], Jigjiga (36.6%) [30], Mecha (75.1%) [31], Ethiopia (38.3%) [32], Sekota Zuria (77.4%) [33], Areka town (75.4%) [34], Wonago (52.4%) [35], and Ambo (35.6%) [36]. However, it was higher than the results of studies in Amibara (8.3%) [37] and the 2005 EDHS report (20%) [38]. Accordingly, 62% (95%CI: 58.40, 65.70) of children aged 12–23 months of age had access to childhood vaccination. The finding was lower than those of studies done in Mecha (98.4%) [31], Jigjiga (73%) [30], Debre Markos (96.9%) [39], Wonago (99.0%) [35], Kwahu Afram Plains, Ghana (97.3%) [29], but higher than that of a study done in Ambo(36.9%) [36]. The continuum of childhood vaccination services in the current study was 46.9% (95%CI: 43.30, 50.80). The finding was lower than the results of studies done in Debre Markos (91.7%) [39], Ethiopia (55.7%) [40], Kwahu Afram Plains, Ghana (87.7%) [29], but higher than that of a study done in Ambo (29.9%) [36]. Additionally, pentavalent-1 to 3 and BCG to measles dropout rates in this study were 33.42 and 17.53%, respectively. The possible explanation for this variation might be the differences in study periods and designs. Another justification might be the current analyses was done in pastoral communities where the necessary information about childhood vaccination was not available. Another reasons could be the differences in health system from country to country. Furthermore, the number of vaccine types in the current assessment of childhood complete vaccination status is different from the previous ones, and this can result in variations in vaccination status of children.
Mothers who lived in rural areas negatively influenced the access to childhood vaccination compared with that of mothers lived in urban areas. This finding was supported by the studies done in Mecha [31], East Gojjam [41] and Jigjiga [30]. The possible justification might be that urban resident mothers might have better information and recognize the importance of vaccination.
Women who had formal education positively influenced access to childhood vaccination compared with non-educated ones. This finding was supported by those of studies done in Kenya [27], Jigjiga, Amibara, and Sekota Zuria [30, 32, 33, 37], Ethiopia, and Nigeria [42]. The possible justification might be that educated mothers might have better knowledge about vaccine-preventable diseases and recognize the importance of vaccination.
Women who received ANC during their last pregnancy positively influenced the access and continuum of the vaccination of children compared with mothers who had no ANC at all. This finding is consistent with other findings in Ethiopia [32, 33, 35, 43, 44], Nigeria [45], Uganda [46], and Kenya [47].
The access and continuum of childhood vaccination were higher among women who gave their last birth at health institutions compared with those delivered at home. This finding was also in line with those of studies conducted in Ethiopia [30,31,32,33, 48] and Kenya [47]. The higher chance of getting access, continuum and complete childhood vaccination of children born to women who had utilized ANC and/ or institutional delivery services could be related to their familiarity to the healthcare systems during their previous visits and health workers’ advice on the vaccination of children.
Women in the rich wealth status positively influenced the access and continuum of the vaccination status of children compared with their counterparts. This finding was consistent with those of other studies in Ethiopia [32, 40, 49], and Bangladesh [50]. The possible justification might be that rich households give more attention to their children. Additionally, they could not suffer from financial scarcity for transportation to get services.
Mothers who had low birth weight children negatively influenced childhood access and continuum of vaccination compared with mothers who had more birth weight children. The possible explanation might be that mothers who had low birth weight children could not take their child for vaccination sessions because they consider their children were not normal and for fear of vaccine side effects. As these mothers might focus on improving their children’s weight, they could not give attention to other child health issues.
This study has a number of limitations. It lacks the effect of vaccine management system and service delivery related factors, like logistics, knowledge of clients, attitude and trained human resources as predictors of childhood vaccination. Besides, it did not cover infrastructure and human resources that might have contributed to the low access and continuum of vaccination. Moreover, the study did not address the reasons for low access and continuum of vaccination and the immune status of vaccinated children.