Effectiveness of PHCU interventions and enhanced headcount to address zero dose and under-immunized children in pastoralist communities: experience from Afar and Somali regions, Ethiopia

Abstract

Background

Reaching and vaccinating zero dose and under-immunized children requires effective strategies and quality data. Primary health care unit level interventions like hands-on training, mentoring, participatory planning and review and enhanced headcount of under two-year children were implemented in four primary health care units Afar and Somali regions. The aim of this manuscript is to describe and share the experience on the effectiveness of these interventions in reaching and vaccinating zero-dose and under immunized children through well planned headcount.

Method

The intended interventions were implemented in four purposely selected woredas from Afar and Somali regions. One primary health care unit was chosen from each woreda based on different criteria. Following the interventions, headcount of under two-year children was conducted in all villages of four primary health care units’ catchment with active engagement of community leaders. Modified periodic enhanced routine immunization template was used to register enumerated children. Identified zero-dose and under immunized children were referred to nearby immunization sites with referral slip for vaccination. Immunization indicators and the reason for missing immunization, descriptive analysis done using Microsoft Excel.

Result

Improved primary health care linkage coupled with strengthened capacity enabled primary health care units to conduct enhanced head count to identify and vaccinate unreached children. The headcount led to the identification of 390 (24%) never vaccinated and 185 (11%) under-immunized children among 1478 enumerated 6 weeks-11 months children in 21 HPs under four primary health care units. Among 1,619 enumerated 12–23 months children, 332 (21%) were zero-doses and 355 (22%) were under-immunized children. Through referral linkage to immunization service, 92% (357/390) of never vaccinated and 97% (179/185) under-immunized 6 weeks − 11 months children were subsequently vaccinated for vaccines they missed. Likewise, 94% (620/658) above one-year children were vaccinated for the measles vaccine. The reasons for failure to vaccinate for 12–23 months old children were access barriers in 70% followed by lack of knowledge (15%).

Conclusion and recommendations

Strengthening the primary health care unit linkage and its technical and managerial capacity accompanied by headcount through the involvement of community leaders can benefit the identification and reach of children missing vaccination and other essential health services.

Introduction

Immunization is one of the most successful, cost-effective public health interventions to reduce child mortality, improve maternal health and combat life threatening diseases such as measles, pneumonia, diarrhea, cervical cancers and others [1, 2]. Besides, evidence reveal that fully vaccination would have benefits on cognitive gains and school-grade attainment that can have broad educational and economic consequences which extend beyond early childhood [3]. Through ensuring herd immunity, population can be indirectly protected from devastating vaccine preventable diseases [4, 5]. It is a key component of primary health care and an indisputable human right [2].

The number of vaccines given as part of Expanded program of immunization (EPI) in Ethiopia has significantly increased. According to the current schedule, Ethiopia provides BCG and OPV-0 at birth; Penta-1, PCV-1, OPV-1 and Rota-1 at age of 6 weeks; Penta-2, PCV-2, OPV-2 and Rota-2 at age of 10 weeks; Penta-3, PCV-3, OPV-3, IPV-1 and Rota-3 at age of 14 weeks; MCV-1 and IPV-2 at 9 months of age and MCV-2 at age of 15 months. Despite substantial achievements in reducing under-five mortality and morbidity and increasing vaccination coverage between 2000 and 2019 in Ethiopia from 20.7% to 60.9% Penta 3 coverage [6], there are continuing disparities in immunization performance and outcomes between and within regions, between urban and rural, and agrarian and pastoralist settings.

According to 2022 WUENIC estimate, Ethiopia stands second among countries with the highest number of zero dose children (next to Nigeria) contributing 1.1 million children to the global prevalence of zero dose children [7]. According to GAVI report [8], in countries like Ethiopia, zero dose children are primarily found in remote rural settings and pastoralist communities such as Afar and Somali regions. The inherently weaker health infrastructure, lifestyle of the pastoralist community, economic deprivation, and limited access to health services present a complex and challenging environment for the delivery of vaccinations. These all necessitate employing a context-based approach and tailored strategy to reach the unreached children for routine immunization services in these settings [9].

Zero-dose children (children not vaccinated for the first dose DPT containing vaccine) and their families face multiple deprivations related to wealth, education, water and sanitation, nutrition, and access to other health services, and they account for one-third of all child deaths in low- and middle-income countries [9]. Reaching zero-dose children and missed communities is therefore critical to achieving the Sustainable Development Goals commitment to “leave no one behind” [9, 10]. Various studies [11] indicate the benefit of reaching zero dose children and show that children who receive the first dose of vaccine tend to receive subsequent doses of vaccines. Targeting this population group would also provide an opportunity to identify, understand and address barriers to under-immunization.

Although different strategies [12] are used to reach zero-dose children and missed communities, the effectiveness of the strategies and data quality problems remain as main challenges to reaching, characterizing, and vaccinating zero-dose children at household level particularly in remote rural and pastoralist communities where most of these children reside. To realize the global vision of leaving no one behind [13], there is a need to design and implement strategies to reach and vaccinate unvaccinated and underserved children at household level.

The Clinton Health Access initiative (CHAI) supported Afar and Somali regions and project woredas (administrative structure equivalent to district) to strengthen management systems and capacity through strengthening governance and leadership on immunization through evidence-based planning, capacity building, supportive supervision, session planning and review meetings at region and woreda level. Despite the immunization program management and leadership capacity established at regional and woreda level, the routine immunization coverage at health center and health post level of these pastoralist areas doesn’t show significant changes. Thus, this PHCU linkage approach involving Health centers, health post and community to reach the unreached children and improve immunization coverage came into picture. To further extend these interventions to primary health care unit (PHCU) level and maximize the outcomes of interventions, CHAI piloted different interventions that contributed to the strengthening of technical and managerial capacity of PHCUs focusing on generating accurate target population data through head count for evidence-based planning and performance monitoring. The aim of interventions was to test how improved technical and managerial capacity at PHCU level coupled with active community engagement can result in improvement of routine immunization performance and reduction of zero dose and under immunized children. Implemented interventions include evidence based participatory planning workshop with engagement of health extension workers (HEW) and community leaders to identify sub villages with low immunization performance, discuss on reasons for low coverage and figure out local solutions. Besides, geospatial mapping of immunization service delivery points, hands-on training of health extension workers at health center level, regular mentoring of HEWs by health center immunization focal person, real data collection on zero dose through house-to-house head count and participatory review meeting to monitor implementation of planned activities and their result were implemented by PHCU with support from woreda health offices.

The aim of this article is to describe and share the experience on the effectiveness of strengthened PHCU (health center, health post and community) linkage to reach, identify, and vaccinate zero dose and under immunized children (children not vaccinated for third dose of DPT containing vaccine) through well planned enhanced head count in Afar and Somali regions.

Objective

The objective of this study is to describe and share the experience on the effectiveness of primary health care unit interventions and enhanced headcount in identifying, reaching and vaccinating zero-dose and under immunized children in selected PHCUs of Afar and Somali regions.

Materials and methods

Study setting

Afar and Somali regions are emerging regions with a high proportion of pastoralist communities and weak immunization programs. The interventions were implemented in four primary health care units (PHCU) selected from CHAI project woredas in Afar and Somali regions based on multiple inclusion criteria.

Study design

Primary Health Care intervention was cross sectional institution-based intervention whereas head count of under two years children was community-based survey. Woredas for implementation of PHCU interventions were purposefully (purposive sampling) chosen from CHAI project woredas in Afar and Somali regions (two from each region). One primary health care unit from each woreda was selected for the interventions using multiple selection criteria. Lists of selected PHCUs are depicted in Table 1; Fig. 1 below. All health posts found in the four PHCUs were part of the interventions.

Table 1.

Geographic location of the selected primary health care units and catchment health posts for PHCU interventions

Regions	Woreda	Selected PHCU	Total Population	Surviving infant	Pregnant Women	Number of HP
Afar	Semu Robi	Kumamie	13,361	359	383	4
Afar	Gewane	Gewane	22,311	600	640	7
Somali	Berano	Dibudajin	19,562	574	618	5
Somali	Denbel	Dure	32,075	943	1014	5
Total			87,309	2477	2656	21

Fig. 1.

Distribution of PHCUs in Afar and Somali regions. Selected for the study

Study population

All PHCUs (including health posts) in four woredas (Gewane and Semu robi woredas from Afar region; and Denbel and Berano woredas from Somali region) and all 6 weeks – 23 months children in the woredas were included in the study population.

Sample size

The four PHCUs from four woredas were considered for the PHCU interventions. Besides, all children under two years of age living in all households of the selected twenty-one kebeles (the lowest administrative structure) of four PHCUs were counted and included in the analysis.

Inclusion criteria

Multiple selection criteria were used to select one PHCU for the intervention from each purposefully chosen woredas. The selection criteria were routine immunization performance (low or medium as measured by pentavalent-3 coverage) as per the regional context, availability of minimum or basic human resource composition at PHCU health center to conduct mentoring of health posts and availability of an average number [4–6] of satellite health posts within catchment area of PHCU.

Data collection tools and procedures

Project reports were used as secondary data source to document information on the results of the interventions. Headcount data was collected using nationally prepared periodic intensified routine immunization (PIRI) template which was adapted to fit for the purpose of the study. The headcount was conducted with team composed of 62 health extension worker and respective community leaders assigned to each kebele. Relevant demographic information, immunization status of each child by antigen (pentavalent-1, pentavalent-3, MCV-1, MCV-2 and fully vaccination) and reasons for missing vaccination were collected moving from house to house. The data collection tool was translated into Amharic for Afar data collectors and Somali language for Somali data collectors. Findings of the head count were summarized and reported in tables designed for the purpose. All identified zero-dose and under immunized children were sent to nearby immunization sites (either health facility or outreach sites) with referral slips to either resume or continue vaccination. Health centers and health posts recorded all referred children on the routine immunization register according to their immunization status and tallied on separate tally sheet prepared for this purpose. The health facilities then reported vaccinations that occurred following a referral linkage to vaccination sites. Immunization Coverage data used for comparison with the result of the headcount was extracted from the national DHIS-2 report of the respective year.

Data management

Data generated from head count exercise was used to compute different immunization indicators that enable to evaluate immunization status in the catchment of respective PHCU (Coverage, dropout rate, extent of Zero doses and under-immunized children). Descriptive analysis of data generated from head count using MS Excel done to understand the immunization status and the reason for missing immunization in the PHCU catchment. Cost per counted child was calculated. Graphs and tables were used to present the findings.

Operational definitions

This study used GAVI definitions [14] for the following words and phrases used in the study.

• Zero dose children: is defined as those children that have not received any routine vaccine. For operational purposes, GAVI defines zero-dose children as those who lack the first dose of diphtheria-tetanus-pertussis-containing vaccine (DTP1) by the end of their first year of life.

• Under immunized children are defined as those missing the third dose of diphtheria, tetanus, and pertussis (DTP)-containing vaccines (DTP3). It doesn’t include never vaccinated and zero dose children.

• Never vaccinated: For operational purpose, never vaccinated is defined as those children who are less than one year of age that have not received first dose of pentavalent vaccine.

• Missed community is home to clusters of zero-dose and under-immunized children. These communities often face multiple deprivations and vulnerabilities, including lack of services, socio-economic inequities and often gender related barriers.

Data quality

To ensure that the headcount was properly conducted, and accurate data generated, a one day training was given to enumerators and kebele leaders on how to conduct the headcount and how to use the tools. Supervision of the teams with random checking of the households was done by 4–5 HC staffs per PHCU. House marking of visited houses was done to ensure that all houses were visited. Collected data were reviewed by the team daily and checked during submission by supervisors.

PHCU interventions

Through primary health care interventions, technical and managerial capability of the primary health care was built to plan and implement strategies that enable them to reach and vaccinate children missing vaccination. To this end, hands-on training was given to immunization focal persons and supervisors from health centers, and health extension workers from all health posts in the catchment of selected PHCUs. Each PHCU conducted one round of participatory planning at PHCU level with active engagement of woreda health office (district health managers and staffs), health center head and staffs, all health extension workers, community leaders and participants from immunization partners. The PHCUs reviewed the earlier year (2021/2022) immunization performance, identified the gaps and challenges that contribute to the high number of zero dose and under immunized children and devise a workable action plan. During planning session, mapping of community settlement considering their mobility was done with village leaders to be used for headcount activity planning. Geospatial mapping of immunization service delivery points was done using geolocation data (coordinates) collected through the SurveyCTO tool. Trained HC immunization focal persons started to visit the health posts to mentor HEWs in their catchment areas to ensure that the knowledge and skills gained during the training were properly implemented in their workplace.

Community engagement ensured

Community leaders from each village were engaged in planning workshop and contributed to the identification of community with low immunization coverage (high zero dose children) at sub village level, creation of context specific and workable solution and reviewing of results of implemented interventions. Besides, community leaders were represented in headcount enumeration team and actively supported the headcount and linking of un/under immunized children to immunization service.

Results

Head count accounted for enumeration of 3242 children under two years of age in twenty-one kebeles (villages) within the catchment of four primary health care units. Among the total enumerated children, 1,623 were between 0 and 11 months of age, including 145 infants under 6 weeks, who were not yet eligible for vaccination. The remaining 1,619 children were aged between 12 and 23 months. Most of the households were visited except a few households which were not accessed due to security problems and mobility of the community. As depicted in Fig. 2 below, the number of children counted, zero dose and under-immunized children varies across primary health care units which was due to variation in their catchment population.

Fig. 2.

Comparison of number of counted children with zero dose and under-immunized children identified during head count by age group and PHCU, April-May 2022

Identified zero doses and under immunized children through headcount

The head count led to the identification of 390 (26%) never vaccinated children and 185 (13%) under-immunized children among the 1,478 enumerated 6 weeks-11 months old children (Table 2). Among 1,619 counted children between 12 and 23 months age from the four PHCUs, it was found that 332 (21%) were zero doses and 355 (22%) were under-immunized. As depicted in Fig. 3 below, the proportion of zero-dose and under immunized children varies across the PHCUs. Dibudajin PHCU reported the highest proportion of 12–23 months age zero dose children which was 23% (65/284) followed by Dure PHCU which was 21% (136/ 634), both from Somali region. Gewane PHCU reported 49% (206/424) of under immunized children followed by Dibudajin PHCU which was 14% (39/284) among counted children.

Table 2.

Number and proportion of counted 6 weeks-11 months age children by immunization status and PHCUs, April- May 2022

S. No	Name of PHCU	Number for 6 weeks-11 months by immunization status					% of 6 weeks-11 children by immunization status
		Total number of children counted	Fully Vaccinated	Vaccinated for age (VFA)	Defaulters*	Never Vaccinated	% of Fully vaccinated	% of VFA**	% of Defaulters	% of Un-immunized (Zero Dose)
1	Gewane	340	19	160	47	114	6%	47%	14%	34%
2	Kumamie	212	23	59	40	90	11%	28%	19%	42%
3	Dibudajin	265	53	89	51	72	20%	34%	19%	27%
4	Dure	661	280	220	47	114	42%	33%	7%	17%
Aggregated		1478	375	528	185	390	25%	36%	13%	26%

*Defaulters defined as those children that missed next doses appropriate for their Age

** VFA – Vaccinated for age

Fig. 3.

Proportion of zero-dose and under immunized children among counted children by age group and PHCUs, April -May 2022

Immunization coverage among enumerated 12–23 months age children

The data generated from the headcount exercise was used to compute local immunization indicators which is vital for evaluation of immunization situation in each PHCU catchment. Accordingly, the proportion of 12–23 months children vaccinated for first dose pentavalent vaccine was 82% for Kumamie, 77% for Dibudajin, 77% for Dure and 72% for Gewane PHCUs.

The proportion of children vaccinated for the third dose of pentavalent vaccine was relatively highest for Kumamie PHCU (79%) followed by Dure PHCU (70%) while Gewane penta-3 coverage was reported to be the lowest (42%). In all four PHCUs, only less than third of counted 12–23 months age children were reported to be vaccinated for the first dose of measles vaccine (MCV-1) with the highest (74%) for Kumamie PHCU and lowest (32%) for Gewane PHCUs (Table 3).

Table 3.

Number, and proportion of counted 12–23 months children with their immunization status, April -May, 2022

S.No	Name of PHCU	Total # counted	Number of counted 12–23 months age children by their Vaccination status							% of counted 12–23 months age children by their Vaccination status							Proportion of dropout rate
			Fully vaccinated	Penta1	Penta3	MCV1	MCV2	Defaulter	Zero Dose	Fully vaccinated	Penta1	Penta3	MCV1	MCV2	Defaulters	Zero Dose	% penta-1-3		%penta1-MCV1	%MCV1-MCV2
1	Gewane	424	136	306	177	136	47	206	82	32%	72%	42%	32%	11%	49%	19%	42%		56%	65%
2	Kumame	277	203	228	220	206	185	25	49	73%	82%	79%	74%	67%	9%	18%	4%		10%	10%
3	Dibudajin	284	180	219	195	180	133	39	65	63%	77%	69%	63%	47%	14%	23%	11%		18%	26%
4	Dure	634	413	463	444	416	317	85	136	65%	73%	70%	66%	50%	13%	21%	4%		10%	24%
Aggregated		1619	1619	1216	1036	938	682	355	332	58%	75%	64%	58%	42%	22%	21%	15%		23%	27%

Comparison of head count result with administrative data

The analysis revealed that there are discrepancies between the number of 12–23 months age children enumerated through headcount and projected surviving infants (based on the census conducted in 2007) of the corresponding year (Fig. 4).

Fig. 4.

Comparison of number of counted 12-23 months age children with 2013 EFY surviving infants calculated from total population by PHCU

As depicted in the Fig. 5, the number of children reported to be vaccinated for first dose of pentavalent vaccine in DHIS-2 routine reported was found to be much higher than the one found during head count, and this is true for all antigens.

Fig. 5.

Comparison of number of children vaccinated for first dose of pentavalent vaccine from DHIS-2 report and head count by PHCU

Further analysis to compare coverage computed from head count data with routine DHIS-2 coverage of the respective year revealed that the vaccination coverage rates obtained through headcount data consistently scored lower than DHIS-2 data for all PHCUs and antigens (Table 4). On average, aggregated pentavalent1 coverage among counted children was 19% point lower than that of DHIS-2 report of respective year, with the highest discrepancy for Dure PHCU (26% point) and lowest for Kumamie PHCU (3% point). Likewise, aggregated coverage of third dose pentavalent was reported to be 21% point lower among counted children compared to respective year DHIS-2 report, the highest being for Dure and Dibudajin PHCU (24% point) and lowest being for Kumamie PHCU (5% point).

Table 4.

Comparison of immunization number and coverage among counted 12–23 months age children and reported coverage through DHIS-2 by PHCU, April-May 2022

Woreda	PHCU	Data Source	Penta1		Penta3			MCV1		Fully vaccinated
			Counted	DHIS-2 Report	Counted		DHIS-2 Report	Counted	DHIS-2 Report	Counted		DHIS-2 Report
Gewane	Gewane	Number	306	516	177		516	136	367	136		281
		Coverage	72%	86%	42%		65%	32%	61%	32%		47%
Semu Robi	Kumamie	Number	228	304	220		304	206	276	203		243
		Coverage	82%	85%	79%		84%	74%	77%	73%		68%
Berano	Dibudajin	Number	219	567	195		567	180	510	180		408
		Coverage	77%	99%	69%		93%	63%	89%	63%		71%
Denbel	Dure	Number	463	938	444		938	416	726	413		726
		Coverage	73%	99%	70%		94%	66%	77%	65%		77%

Barriers to access vaccination

As part of the head count, the underlying reasons why zero dose children were not vaccinated and under immunized children did not receive subsequent vaccination doses was gathered. A summary of the reasons is provided below in Fig. 6.

Fig. 6.

Reasons for missing vaccination for 12-23 months age children, April-May 2022

The most common reasons for missing doses of vaccines were reported to be distant vaccination sites, mobility of the community and lack of means of transportation to vaccination posts which can be either outreach sites or health facilities. The summary of the reasons reveal that 70% of the reasons1 for failing to vaccinate for 12–23 months age children who missed vaccination (either ZD or under-immunized) were related to access barriers (such as geographic distance of vaccination post, temporary family relocation, transportation access and busyness of the mothers/care takers) followed by lack of knowledge (15%) about importance of vaccination and return date for the next dose. The contribution of unavailability of immunization service at vaccination sites due to absence of vaccinator or vaccine stock out (either static or outreach site) was found to be 14%.

Vaccination response to children following head count

All identified zero dose and under immunized children during the head count were sent to immunization sites with referral slip and were tracked for vaccinations by health facilities. Data collected from health posts and HCs revealed that, on average, 92% (357/390) of zero dose children and 97% (179/185) of defaulters (those children missed either penta-2, penta-3 or MCV-1 ) of 6weeks – 11 months children received their vaccination. As depicted in Fig. 7, Kumamie and Dibudajin PHCUs were able to vaccinate 97% and 96% of identified zero dose children, respectively, while the performance of Dure PHCU was reported to be low (84%). Similarly, Kumamie and Dibudajin PHCUs were able to vaccinate 100% and 98% of identified defaulter children, respectively (Fig. 8).

Fig. 7.

Number and proportion of 6 weeks–11months age zero dose children vaccinated for first dose of pentavalent vaccine following head count by PHCU, April -May 2022

Fig. 8.

Number of 6 weeks–11month age defaulters Children that continued their missed vaccination series appropriate for their age following head count by PHCU, April-May 2022

Vaccination of 12–23 months age children

Since there was no endorsed national catch-up vaccination guideline (endorsed in November 2022) at the time of implementation of the head count, that guides what should be done for identified zero dose and under immunized children beyond infancy period, the PHCUs faced difficulty in addressing 12–23 months age children. However, as per the guidance provided from National Implementation Guideline (2021) for Expanded Program on Immunization2 (12), PHCUs vaccinated and reported that 95% (315/323) of zero dose (never vaccinated) and 86% (305 /335) of under immunized were vaccinated at least for measles vaccine.

Cost per vaccinated child as part of head count

One of the pieces of evidence generated during this work was to assess the feasibility (in terms financial cost) of head count to identify and vaccinate children missing vaccine doses particularly in underserved communities where considerable number of zero doses and/or under immunized children reside. The summary of financial cost3 for headcount across all PHCUs revealed that $1.42 was invested to count each child4 whereas $3.64 was invested to reach and vaccinate zero dose and under immunized child, with variation of the cost per missed child from $4.78 for Kumamie PHCU to $2.75 for Gewane PHCU (Table 5). Besides other local factors that incur additional costs (such as distance, geographic setup, community settlement etc.), the analysis revealed that proportion of missed children for vaccination (both zero-dose and under immunized children) is one of the factors impacting cost per missed child; however, this requires additional study. The lowest cost per unvaccinated child ($2.75) was seen for Gewane, the PHCU with the highest % of zero dose and under immunized children (58%) whereas the highest cost per unvaccinated child was reported for Kumamie PHCU.

Table 5.

Summary of financial cost per vaccinated children in piloted PHCUs

Woreda	PHCU	Total counted children 0–11 months	Total counted children 12–23 months	Total counted children	Total ZD and UI counted	% of ZD and UI children	Budget Support provided by CHAI for Head count (ETB)	Cost per surveyed child in ETB	Cost per child in USD (52 ETB/USD)	Cost per identified ZD and UI in USD
Gewane	Gewane	353	424	777	449	58%	61,750	79.5	$1.59	$2.75
Semurobi	Kumamie	222	277	499	204	41%	48,800	97.8	$1.96	$4.78
Denbel	Dure	285	284	569	227	40%	68,640	89.2	$1.78	$4.47
Berano	Dibudajin	763	634	1397	382	27%	50,770	49.1	$0.98	$3.59
Total		1623	1619	3242	1262	39%	229,960	70.9	$1.42	$3.64

Discussion

Reaching and vaccinating zero-dose and under immunized children with context specific and feasible strategy is imperative to improve vaccination coverage and reduce immunization inequities within populations by leaving no child behind [10]. The experience from piloting PHCU level interventions revealed that improved technical and managerial capability of primary health care unit in planning to identify and reach unreached children and communities, to monitor their performance, to engage community in immunization critical activities contributes to improved immunization performance. Compared to traditional way of conducting head counts [12], well planned and monitored head count conducted with the active engagement of the community leaders followed by vaccination response and tracking of referred children to vaccination sites enabled to effectively reach, identify and vaccinate children missing vaccination at household level with relatively low operational cost. Contrary to traditional head count, prior planning and community settlement mapping with village leaders considering mobile nature of the community has contributed for the effectiveness of identification and vaccination of ZD children [12]. Through this approach, over 92% (357/390) of identified zero dose and 97% (179/185) under-immunized 6 weeks-11 months age children were subsequently vaccinated.

Besides, the data gathered from headcount provided valuable and accurate information enabling evidence-based target setting during planning, computing local immunization indicators to evaluate immunization situation across each PHCU catchment area, identify reasons for failure to vaccinate or continue vaccination which can be input for evidence-based planning and program monitoring. This can minimize the challenges related to target setting. Across all PHCUs, the reported number of vaccinated children and the immunization coverage calculated from this routine DHIS-2 report were consistently higher than the one computed from head count which can be due to the tendency of health facilities to overreport their performance and poor data management [15–17]. Verification of the reasons for these discrepancies across all piloted PHCUs requires further study.

One of the pieces of critical information obtained from enhanced headcount was the reasons for not vaccinated for zero doses children or not continuing vaccination for under immunized children. To this end, the aggregated summary of the reasons revealed that accessibility to immunization service including geographical distance, family’s relocation, lack of transportation and lack of time are the major (70%) reasons for failure to vaccinate children followed by unavailability of service (15%) and lack of adequate information (14%). This information is imperative in informing the design of evidence based operational plans that address obstacles for getting immunization in similar setting. Identified missed communities with high number of missed children can be geospatially mapped against existing immunization service points and redesigned to align with community settlement and movement nature in the pastoralist community.

Despite guidance of most national immunization guidelines [18–20] to conduct head count, it is not implemented at large scale to accurately define target population as well as identifying unvaccinated children claiming as expensive and unsustainable strategy [12]. Though there was no documented evidence for cost of head count to compare with, the enhanced head count approach enabled to reach and vaccinate zero dose and unvaccinated children in missed communities with relatively high number of zero dose and under immunized children at minimum possible cost and locally available resources. The analysis of the evidence across all four PHCUs showed that as the number of unvaccinated children increases the cost per counted child decreases which makes it more applicable for communities with high number of unvaccinated children. In addition to gathering important data that are useful for planning, resource allocation and program monitoring, to further maximize the efficiency of head count, other maternal and child health activities can be integrated. However, this requires further study.

Limitation

As the intervention was conducted in a pastoralist context, it might be difficult to generalize the findings to larger geographical area in the country including agrarian regions. Another limitation of this study was the limited availability of literature on the effectiveness of headcounts and the role of referral linkages in connecting missed children to vaccination services. This made it difficult to compare and contextualize the findings within existing evidence. Since there was no documented evidence on the cost of implementation of head count, there was difficulty to discuss on the consistency of the finding. While the identification and referral of zero-dose and under-immunized children has proven to be an effective and feasible strategy for improving vaccination coverage, the study did not explore how this approach could be sustained across different contexts.

Conclusion and recommendation

The findings from the PHCU intervention showed that strengthening technical and managerial capacity of PHCUs to generate local and reliable evidence for planning, allocation of limited resource and program monitoring and active community engagement enable to reach, identify, and vaccinate children missing vaccination at household level through head count with relatively low operational cost. Combined with other interventions like desk review of available data and geospatial mapping of missed communities, enhanced head count approach can be efficiently employed to reach, identify, and vaccinate unimmunized and under immunized children in communities with relatively high number of unvaccinated and under immunized children. As most of zero dose and under immunized children family are deprived of other essential maternal and child health services, well planned head-count activity can also be used to gather information on and deliver other maternal and child health interventions including nutritional screening, head count of out of schoolgirls for HPV vaccination, pregnant women for ANCs etc. taking into account local context [to maximize efficiency and value for money]. This approach can also be applied to children up to five years of age in geographic areas at risk of vaccine-preventable disease outbreaks, where zero-dose and under-immunized children have accumulated over time. Following the identification of missed children through headcounts, it is recommended to implement well-planned outreach vaccination strategies to ensure a timely and effective response. It is recommended that similar interventional study should be done in non-pastoralist agrarian regions to see how this approach is effective in different circumstances.

Abbreviations

CHAI

Clinton health access initiative

DPT

Vaccine containing “Diphtheria Pertussis and Tetanus”

EPI

Expanded program of immunization

PHCU

Primary Health Care Unit

HEW

Health Extension Workers

GAVI

Global Alliance for vaccine and Immunization

MCV

Measles containing vaccines

WHO

World Health Organization

WUENIC

WHO and UNICEF estimates of national immunization coverage

Authors’ contributions

Design the research: HB, D.D & YT; Supervision of Data collection and collation of collected data: K.B, Z.S; Analysis of the result: D.D, H.B & Y.T; Manuscript writing: D.D, Y.T & H.B; Review the manuscript: H.B, T.M, and AA; interpretation of data; All Authors.

Funding

The study used the data from Project implementation which was funded by Gate foundation. There was no additional fund required to undertake this study.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

The study was approved by the health research Ethics review Committee of both Afar (Ref.No QAF B01-3629) and Somali (Ref.No SRHB-18-6377) Region Health Bureaus. Informed consent was obtained from parent and/or guardian of all study participants during headcount.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.