Trends and insights of data quality in the expanded programme on immunization East and Southern Africa sub region: (1974-2024)

¹WHO Inter-Country Support Team office for East and Southern Africa, Harare, Zimbabwe

^&Corresponding author
Maryanna Akinyi Ochieng, WHO Inter-Country Support Team office for East and Southern Africa, Harare, Zimbabwe

Introduction    

Data is defined by the World Health Organization (WHO) as systematic information on the characteristics of statistical units within defined aggregates, consisting of records and documentation [1]. Globally, data is a public health good that plays a crucial role in public health decision-making, research, and development. Data quality refers to various characteristics of datasets, including the correspondence between records and datasets, the frequency of missing values, and the accuracy of information, aspects that are often compromised in low- and middle-income countries and where most of the East and Southern Africa (ESA) countries belong [2,3].

Quality data is a foundation upon which informed decisions are made and plays a vital role in planning, implementation and evaluation of immunization programmes and other global health interventions [2-4]. Quality immunization data is essential for monitoring coverage, assessing equity gaps, informing microplanning, monitoring cold chain functionality, mobilising resources and policy formulation. Global and regional strategies have reinforced the need for data as a cross-cutting enabler of immunizations equity, sustainability, and resilience [5,6]. The Addis Declaration on Immunisation (ADI) commits African governments to strengthen national information systems and improve the quality and use of immunisation data for better decision-making and accountability.

During the smallpox eradication campaign from 1966 to 1977, the Expanded Programme on Immunization (EPI) relied on paper-based data tools to record and transmit information, which posed challenges in accuracy and timeliness [7,8]. Initially, vaccinations were conducted through periodic mobile teams, but EPI transitioned to a regular routine immunization system, enabling more children to receive vaccines daily and expanding data collection to include various antigens. This shift improved vaccine coverage and monitoring, influencing the development of modern digital health tools such as electronic health records and automated surveillance systems. These advancements have since enhanced data accuracy, accessibility, and efficiency in global immunization efforts [9,10].

Technological advancements have significantly transformed immunization data collection, analysis, and utilization. In the early 2000s, electronic health management information systems (HMIS) marked a transition from traditional paper-based systems to digital platforms, improving data efficiency and accessibility. The development of District Health Information System 2 (DHIS2), an open-source platform designed for integration and data exchange, was a major milestone towards centralized archiving through national health data warehouses [11-13]. By 2011, Uganda became one of the first ESA subregional countries to implement a nationwide rollout of DHIS2, and since then, most East and Southern African (ESA) countries have institutionalized it within their national health systems [14]. These digital systems have replaced conventional paper-based tools, enabling real-time data entry, monitoring, and sharing across various health system levels. Complementary technologies such as electronic temperature monitoring devices, geospatial information systems (GIS), and electronic immunization registries have been introduced further strengthening the quality, accessibility, and utilization of immunization data [15,16].

As the role of data in policy formulation and strategic planning has become more central, there has been a growing emphasis on improving data quality [17,18]. This has led to the adoption of standardized data quality indicators like completeness and timeliness, used to measure and improve performance. The electronic Joint Reporting Form (eJRF), a collaborative data collection tool managed by WHO and UNICEF, has provided a standardized mechanism for tracking and collecting data quality indicators across countries [19]. In addition, Data Quality Reviews (DQRs), and data triangulation workshops have proven instrumental in validating reported data and promoting a culture of data use within national programmes.

Therefore, this paper aims to document the evolution of EPI data from its initiation in 1974 to 2023, providing a comprehensive analysis of its development over the decades. It will highlight key achievements, structural and operational bottlenecks, and the role of technological advancements in shaping data collection, transmission, and presentation. Additionally, it will explore areas for integration, focusing on cost-effective mechanisms to enhance data quality and accessibility, ultimately improving decision-making processes, particularly in the ESA subregion. The paper will serve as a valuable reference for immunization stakeholders and partners, particularly in the ESA subregion, by offering insights into historical trends, current challenges, and future opportunities for strengthening immunization records and data management systems. It will provide evidence-based recommendations for planning, monitoring, and intervention strategies aimed at optimizing immunization programs. Special emphasis will be placed on improving data accuracy, completeness, and interoperability to support effective policy formulation and resource allocation.

Furthermore, the paper will examine the impact of digital transformation on immunization data management, including innovations such as electronic health records, real-time reporting systems, and the integration of artificial intelligence and machine learning for predictive analytics. By assessing these advancements, the paper will identify key areas for improvement and propose strategies for enhancing data-driven decision-making and ensuring sustainability in immunization efforts. Ultimately, this paper seeks to contribute to the broader conversation on strengthening immunization data governance, fostering collaboration among key stakeholders, and advocating for improved data policies that enhance the reliability and accessibility of immunization information in the ESA sub-region.

Methods     

Study design: we conducted a descriptive mixed-method secondary analysis, incorporating both qualitative and quantitative approaches, on data compiled through the WHO-UNICEF Joint Reporting Form. This study design aimed to assess immunization data from 20 countries in East and Southern Africa (ESA) by systematically reviewing existing datasets rather than collecting new primary data. The quantitative component focused on statistical trends, completeness of reporting, and discrepancies in submitted records, while the qualitative analysis examined contextual factors influencing data collection, transmission, and utilization within national health systems. By combining these methods, we aimed to provide a comprehensive evaluation of immunization data management, highlighting the structural and technological aspects of reporting processes across the ESA sub-region. Immunization programs began in some countries earlier than others, but consistent and comparable data have only been available regionally since 2004. Quantitative data were analysed using Microsoft Excel to identify statistical trends, assess reporting completeness, and uncover discrepancies. Qualitative analysis was conducted to examine the systemic and contextual factors that influence data collection, transmission, and utilization. This approach contributed to a comprehensive understanding of the structural and technological aspects shaping immunization data practices across the subregion.

Variables: the variables used in this study include the following, the completeness of district-level reporting, dropout rates from DTP1 to DTP3, and the proportion of districts lacking coverage data for key antigens for DTP3 and MCV1. These are essential for assessing the quality of immunization data across ESA countries. Completeness serves as a baseline indicator of consistency in reporting, while dropout rates reveal gaps in follow-up and potential issues in service delivery. Missing coverage data indicates weaknesses in surveillance and information systems, particularly at sub-national levels. Monitoring these variables over time not only uncovers structural and operational gaps but also facilitates targeted interventions to enhance data accuracy, timeliness, and usage core elements of an effective immunization data ecosystem.

Data source: we gathered EPI data submitted by the 20 ESA countries from 2004 to 2024 though WHO-UNICEF JRF. The data can be accessed from the public domain. The information was complemented by quantitative data from comprehensive EPI review reports conducted in the countries, EPI managers´ meetings reports and assessments including post-introduction evaluation and effective vaccines management reports. We also noted that while the Expanded Program on Immunization (EPI) was established earlier in some countries, such as South Africa, before 1975, and others by 1990, relevant data for this study were only available from 2000 in a few countries and more widely accessible across the majority of ESA countries by 2004. Consequently, we utilized secondary data from 2004 onwards, retrieved from the WHO-UNICEF Joint Reporting Form repository.

Results     

Our study found that the Eastern and Southern Africa (ESA) subregion initially comprised 19 countries or territories until 2011, when South Sudan was added as the 20th country. For our analysis, we examined data from 2004, covering a period of approximately 20 years. The completeness of reports from various countries varied, with mean values ranging from 0.86 to 1.82; Seychelles recorded the highest completeness (Table 1). Some countries exhibited outliers, reporting more district-level submissions than expected. Notably, Seychelles reported twice the expected completeness in 2011 and 2012, while Lesotho did so in 2006 and Eritrea in 2020. During the review period, Malawi, Mauritius, and Rwanda achieved a 100% completeness rate for district reports. In contrast, Ethiopia recorded the lowest completeness rate at just 8% in 2016, with Zimbabwe also showing 8% in both 2015 and 2016. Similarly, Tanzania had an 8% completeness rate in 2019, and South Africa recorded 9% in 2004. Additionally, Zambia and Namibia reported 0% completeness in 2005 and 2019, respectively; however it seems to be errors in filling the WHO/UNICEF joint reporting forms. The number of countries with suboptimal completeness ranged from 85% between 2022 and 2024 to 42.37% in 2007. During the study period, the percentage of districts reporting DTP1 -DTP3 dropout rates greater than 10% varied significantly across countries in the ESA subregion. The average dropout rate ranged from as low as 1% in Rwanda to as high as 68.6% in South Sudan. An outlier was identified in the data from Eswatini, which reported a figure of 21,000 likely a data error and this was excluded from the comparative analysis. Overall, the subregional average indicated that 23.98% of districts reported dropout rates above 10% (Table 2).

When comparing annual performance, 2024 showed the best results, with no countries reporting districts with dropout rates exceeding 10%. This was followed by 2019, where only 15.16% of districts surpassed the 10% dropout threshold. In contrast, 2007 faced the most significant dropout challenges, with 38.41% of districts reporting rates above 10%, although this figure demonstrated a steady decline through to 2022. Examining the percentage of countries where more than 20% of districts had dropout rates above 10%, 2007 saw the highest prevalence, with 68.42% of countries affected. The lowest levels were observed in 2024 (0%), followed by 2023 and 2019, each at 25%. These findings highlight an encouraging trend: a decline in both the number of high-dropout districts and the number of countries facing widespread dropout challenges, signaling progress toward improved immunization coverage across the subregion.

In our study, we identified several inconsistencies in the reporting of DTP3 vaccination coverage across countries in ESA countries during the study period. Some countries did not submit DTP3 coverage data, and discrepancies were observed between the reported figures and the WHO/UNICEF Joint Reporting Form. Notably, some countries indicated that 100% of their districts had failed to report DTP3 coverage (Table 3), despite the data matrix suggesting otherwise. These discrepancies were particularly evident in Seychelles (in the years 2009, 2011, 2015, and 2022), South Africa (2007 and 2009), Rwanda (2009 and 2010), and in Eritrea (2004), Lesotho (2007), Uganda (2010), Mozambique (2016), and Malawi (2010). In contrast, Botswana, Comoros, Eswatini, Kenya, and Mauritius reported complete district-level DTP3 coverage throughout the entire study period. Among the countries that submitted data without errors but still had a significant proportion of districts not reporting DTP3 coverage, Zambia had 3.4% of districts unreported, and South Sudan had 1.7%. When we assessed the proportion of affected countries across the subregion by year, the highest level of reporting gaps was recorded in 2005, when 26.3% of countries had incomplete data. In contrast, 2024 showed the best performance, with no countries reporting gaps, followed by just 5% of countries affected in both 2020 and 2021. Overall, the findings indicate a clear improvement in data completeness and reporting consistency over time.

n our analysis of MCV1 coverage reporting across ESA countries, we identified significant inconsistencies that impact data quality and informed decision-making. Several countries reported that 100% of their districts failed to submit MCV1 coverage data at the national level. This issue was most pronounced in Seychelles, which exhibited gaps in eight different years: 2004, 2005, 2006, 2007, 2009, 2011, 2015, and 2022 (Table 4). Other countries with reported gaps included South Africa (2007 and 2009), Rwanda (2009 and 2010), Mozambique (2016), Malawi (2020), Lesotho (2007), and Eritrea (2004). Despite these reported gaps, the total number of children vaccinated with MCV1 was still included in national figures from these countries, suggesting a disconnect between district-level reporting and national data aggregation. Eswatini was the only country to consistently report complete MCV1 coverage at the district level throughout the study period. Excluding countries with obvious reporting anomalies, Tanzania, Botswana, and Mauritius had average missing district report rates of 12%, 11.5%, and 10.5%, respectively. From a temporal perspective, the year 2004 showed the highest rate of countries with missing MCV1 district data at 94.7%, while 2024 indicated complete reporting across all countries. Additionally, there was 5% missing data in 2012, 2020, and 2021. These findings reflect a positive trend in data completeness and reliability over time, which is crucial for evidence-based planning and programmatic decision-making.

In our assessment of DTP1 to DTP3 vaccination coverage drop-out rates across ESA countries, several countries reported negative drop-out rates. This indicates that more children received the third dose (DTP3) than the first dose (DTP1) during specific reporting years. This phenomenon was noted in Mauritius on six occasions: 2006, 2008, 2009, 2013, 2015, and 2020 (Table 5). Seychelles recorded negative drop-out rates in four years: 2005, 2011, 2014, and 2015. Rwanda experienced this in four years as well: 2007, 2009, 2020, and 2023. Additionally, negative drop-out rates were seen in Botswana (2006), Eritrea (2023), Eswatini (2014 and 2015), Ethiopia (2011), Kenya (2023 and 2024), Lesotho (2023 and 2024), Malawi (2008 and 2009), Madagascar (2005), and Uganda (2024). For countries that did not report negative drop-out rates, the lowest average drop-out rates were found in Tanzania and Zambia, both at 5.6%, followed by Namibia at 9%. And the highest was South Sudan 18.4% followed by Mozambique 10.7%. When analysed by year, no countries reported negative drop-out rates in 2004, 2012, or during the period from 2016 to 2021. However, 2023 marked the highest proportion of countries with negative drop-out rates, with 20% affected.

Discussion     

While our study highlighted improvements in data completeness and reporting accuracy across Eastern and Southern Africa, we also identified ongoing challenges that compromise the reliability and usefulness of immunization data. A major issue is the inconsistency between national and district-level reporting. Often, coverage figures submitted to WHO/UNICEF at the national level do not match those reported or not reported at the district level. This discrepancy is especially noticeable in DTP3 and MCV1 data, where some countries reported 100% non-reporting from districts, yet still presented national coverage figures.

Another concerning trend is the occurrence of negative dropout rates, which may indicate flaws in data collection, misreporting of late catch-up vaccinations, or poor estimation of population denominators. Additionally, a small number of countries reported either over-complete or zero completeness in their district submissions, likely due to data entry errors or a lack of capacity to validate submissions before final reporting. To address these challenges, we recommend several corrective measures. First, it is crucial to strengthen data validation mechanisms at both national and subnational levels. This should include routine internal consistency checks and automated flagging of outliers during data aggregation. Second, investing in digitized and interoperable health information systems can help minimize human error and facilitate real-time tracking of district-level reporting gaps. Third, tailored capacity-building initiatives that focus on data management, the use of reporting tools, and subnational accountability will ensure frontline personnel are equipped with the necessary skills and knowledge to report accurately. Fourth, regional partners should encourage peer review mechanisms and cross-country learning platforms to share best practices for improving data quality. Finally, establishing routine feedback loops between national programs and districts along with transparent sharing of coverage and dropout dashboards can help foster a culture of data ownership and responsiveness. By addressing these systemic weaknesses, we can enhance the integrity of immunization data, ensuring that programmatic decisions are based on reliable evidence. This will ultimately advance progress toward equitable vaccine coverage and improved public health outcomes across the ESA subregion.

Study limitations: the study has several limitations, mainly due to its reliance on secondary data rather than primary sources, which restricts empirical validation of technological advancements in immunization data management. It does not extensively explore sociopolitical influences, including government policies, political stability, and funding disparities that shape data governance in ESA countries. Additionally, while issues related to data quality assessment, such as inconsistencies in reporting, verification methods, and discrepancies between digital and paper-based records, were identified, they were not fully addressed due to field visit constraints. Generalizing findings across ESA countries also presents challenges, as variations in infrastructure, adoption rates, and health system integration were not comprehensively examined. Furthermore, the study lacks a detailed cost-benefit analysis and a long-term sustainability plan for transitioning to digital immunization data systems, potentially impacting the feasibility of widespread implementation.

Conclusion     

In conclusion, our comprehensive review of immunization data from ESA countries over the past 20 years has revealed both significant progress and ongoing challenges in data quality, reporting consistency, and the performance of surveillance systems. We have observed notable improvements in district-level reporting completeness, especially in recent years, as well as a decline in dropout rates from DTP1 to DTP3 and fewer districts reporting missing coverage for MCV1. However, critical data anomalies such as negative dropout rates, discrepancies between district and national figures, and issues with reporting completeness underscore persistent systemic vulnerabilities. These inconsistencies undermine the reliability of administrative data, limiting the region's ability to make timely, evidence-based decisions for immunization programs and outbreak prevention. To build on these achievements and close remaining gaps, robust corrective measures are essential. These measures include strengthening data validation protocols, expanding digital reporting platforms, and investing in targeted capacity-building efforts at subnational levels. Additionally, fostering peer exchange, establishing accountability frameworks, and integrating quality assurance checks into routine surveillance practices can help reinforce data integrity. By addressing these structural issues, countries in the Eastern and Southern Africa subregion will be better positioned to generate reliable data, optimize immunization delivery, and accelerate progress toward achieving universal vaccine coverage and improved public health outcomes. This work highlights the importance of sustained investment in data systems as a cornerstone of resilient and equitable immunization programs.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Maryanna Ochieng and Daudi Manyanga conceptualized and designed the study, and constructed the background information, data collection, study analysis, interpretation, discussion, critical review and organization of the entire manuscript for publication. Charles Byabamazima, Brine Masvikeni and Sarah reviewed the manuscript and contributed to the discussion and conclusion. All the authors read and approved the final version of this manuscript .

Acknowledgments     

We acknowledge efforts made by all Surveillance Officers and Data Managers from Ministries of Health, WHO and other partners in the ESA countries for their untiring efforts till polio is eradicated.

Tables and figures     

Table 1: distribution of completeness of district reports at national levels in ESA countries (2004 - 2024)

Table 2: trend of countries with districts reporting DTP1-DTP3 dropout rates above 10% in the ESA sub-region (2004 - 2024)

Table 3: documented percentage of districts that did not report DTP3 vaccination coverage in ESA Countries (2004 - 2024)

Table 4: reported percentage of districts that did not report MCV1 vaccination coverage by country in the ESA sub-region (2004 - 2024)

Table 5: observed progress over time in DTP1 to DTP3 vaccination dropout rates in ESA countries (2004 - 2024)

References