Full immunization coverage and its associated factors among children aged 12–23 months in Ethiopia: further analysis from the 2016 Ethiopia demographic and health survey

Vaccination is one of the prevention strategies for common childhood illnesses. It prevents morbidities and mortalities from diphtheria, hepatitis B, measles, mumps, pertussis, pneumonia, polio, rotavirus diarrhea, rubella, cervical cancer, and tetanus [1, 2]. Vaccine preventable diseases (VPDs) account for 17% of the global under five mortality per annum [3]. According to World Health Organization (WHO) 2017 report, 116.2 million infants (85%) received the third doses of DPT, and worldwide, 123 countries reached the third dose of diphtheria, pertussis, and tetanus (DPT3) coverage to 90%. Despite the increasing uptake of new and underused vaccines, still an estimated 19.9 million children under the age of 1 year have not received DTP3 vaccine [1, 4‐6]. Further improvement of global immunization coverage would prevent an additional 1.5 million deaths [3]. According to a case-based surveillance, the annual incidence of measles was estimated at 29.1 cases per 1 million people [7].

Expanded program of immunization (EPI) was launched by WHO in 1974 with the objectives of reducing morbidity and mortality from six VPDs. Ethiopia started the EPI program in 1980 with a longer-term goal of achieving 90% DPT3 coverage in all regions through strategies of reaching every district (RED) and sustainable outreach service (SOS) approaches. In the Ethiopia health care system, immunization is provided free of charge and services are available from the smallest health post level to the highest hospitals [8].

According to guidelines developed by the World Health Organization (WHO), children are considered fully immunized when they have received one dose of Bacillus Calmette Guerin (BCG), three doses of DPT, three doses of polio vaccines, and one dose of measles vaccination by the age of 9–12 months [9, 10]. Ethiopia has incorporated Haemophilus influenza type B (HiB) and hepatitis-B (HepB) antigens to the previous DPT vaccines and replaced as Pentavalent vaccine (DPT plus Hep B and Hib) [1, 3, 8, 11]. A variety of vaccines, of which the Pneumococcal conjugate vaccine (PCV), Rota, and Human papilloma (HPV) vaccines were the most recent have been introduced into the national EPI service overtime. Different findings showed that the proportion of full immunization coverage in the country ranged from 36.6% in Somalia region to 100% in Addis Ababa [1, 4, 10, 12‐17]. Factors associated with child full immunization included socio-demographic characteristics (maternal educational status and residence), health service delivery (place of delivery, ANC follow up, vaccine availability residence, and cold chain management) [1, 4, 10, 12‐22].

Although some community based works are available with different findings, no study has shown the overall national full immunization coverage after the new vaccines have been introduced into the EPI schedule. Therefore, the objective of this study was to measure the full immunization coverage and associated factors among children aged 12–23 months in Ethiopia in order to help planners assess the progress of the national full immunization coverage.

This study revealed that the overall full immunization coverage of Ethiopia was 38.3%, much lower than the 86% Government report and less promising to meet the 2020 health sector transformation plan of 95% [8, 23]. Vaccine specific full immunization coverage’s among children were 56.1% for Pentavalent third dose and 57.8% for Measles, below the Federal Ministry of Health 2015 report of 94% for both of them [8]. The possible reasons for the discrepancies between the national reports and this study might be spurious and false reports from health facilities.

This study also showed differences between full immunization and vaccine specific full dose coverage’s. The possible explanations for the variations might be the stock out of vaccines and the side effects of multiple injections. Furthermore as shown in the Table 2, full immunization coverage was in Ethiopia highly varies among administrative regions, ranging from 8.8% in Afar to 86.8% in Addis Ababa. The possible reasons might be socio-demographic and health seeking behavior differences among regions. In addition, most of the regions with low full immunization coverage had weak health care systems which led to low uptake of vaccines. Moreover, some of the regions like Afar and Somalia had hard to reach areas are nomadic and pastoralist inhabitants with no permanent residence.

This finding of full immunization coverage was lower than those of studies conducted in Togo (63.7%), Cameroon (53.6%), Timor-Leste (52.6%), Uganda (52.5%), Coted’Ivoire (50.5%) DR Congo (49.8%), and Haiti (45.8%) [1, 4, 20, 24, 25]. It was higher than findings in Somalia (11.6%), Mauritania (35.3), Nigeria (33.2%), Chad (11.4%), and the Republic of Central Africa (17.3%) [25, 26]. The possible explanations might be differences in study periods and number of vaccines Like PCV and Rota incorporated in the expanded program of immunization of Ethiopia. Health system differences among countries are also possible explanations for the observed differences. The full immunization coverage finding in this study was significantly higher than 2005 and 2011 EDHS reports of 19 and 24%, respectively [14]. This might be due to tremendous efforts of the Government to realize the millennium development goal of reducing child mortality from vaccine preventable diseases.

Maternal characteristics, residence, educational level, sex of household head, employment, wealth index, ANC follow up and place of delivery were factors associated with full immunization coverage among 12–23 months of age children. Rural residence was associated with lower full immunization of children compared to urban dwellings. This finding is in agreement with those of studies conducted in Arbaminch, Lay Armachio, and Jigijiga of Ethiopia, and Nigeria [9, 13, 14, 17]. This might be due to less accessibility of health facilities to EPI and differences in awareness about immunization. Maternal educational status of primary school and above associated with an increased full immunization of children. This finding is in agreement with the results of previous studies conducted in Ethiopia, Togo, Arbaminch, and Southwest Ethiopia [14, 17, 27‐29]. The full immunization of children with female household heads was lower compared to children who had male household heads. This might be because of high workload and family responsibilities women may not heed EPI schedules for children vaccination. This finding was supported by that of a study conducted in Togo [20]. The full immunization of children whose mothers had ANC follow ups was three times higher than that of children whose mothers had no follow ups. This is supported by the results of previous studies conducted in Togo and Ethiopia [10, 12, 20, 30]. This might be because women who attend follow ANC may get counseling about child immunization in the postnatal period. The children of middle income and rich mothers were associated with higher full immunization than the children of poor mothers. This might be due to differences in child care practice, better health seeking behavior, and health care access. This finding was supported by studies conducted in Nigeria, Togo, and Southwest Ethiopia [9, 12, 14, 20, 22, 29]. The children of women who delivered at health facilities were two times more likely to receive full immunization compared to those of women who had home delivery. This finding was concordat with those of studies in Nigeria and Ethiopia [9, 17, 20, 22, 30]. This might be due to the fact that some vaccines, like BCG and OPV 0 are often given immediately after birth at health facilities. The children of employed mothers were associated with increased fully immunization compared to those of unemployed ones. This might be due to better information access about disease preventions, like immunization.

Sine not all children had vaccination cards, information about immunization status had to be limited the mothers’ verbal responses which were found to be prone to recall bias. Besides, having been based on secondary data analysis, this survey could not assess factors relating to the supply side and health system.

Full immunization coverage in Ethiopia was significantly lower than the global target. Female household head and rural dwelling were negatively associated with full immunization. In contrast higher maternal education, employment, middle and rich economic status, ANC follow up, and delivery at health facility were positively associated with full immunization among 12–23 months old children. This suggests that improved health education and service expansion to remote areas are necessary to step immunization access.