The World Health Organisation defines child maltreatment (CM) as a major public health concern [1]. Worldwide, an estimated 60% of children less than five years of age experience physical and/or psychological violence by their caregivers, and about 20% of women and 14% of men report childhood sexual abuse [2, 3], with considerable variation between continents and countries [3]. Health and wellbeing depend on the interaction of multiple protective and risk factors, particularly during sensitive and critical periods of development of infants, children, adolescents and youth, and across generations [4]. CM has immediate, cumulative and long-lasting negative effects on development, health and wellbeing [2, 5–7]. These adverse experiences can have social and health consequences that influence life course trajectories, impairing educational achievement and employment, with far-reaching societal and economic impacts [1, 8]. Despite considerable European investments in child protection policies and legal frameworks to safeguard children’s rights [9], CM remains under-identified in health and social care (HSC) systems. For example, among children under five, hospitalisations for physical abuse are estimated at 18/100,000 per year in five European countries [10], although self-report studies estimate the incidence of childhood physical abuse to be much higher [11, 12], with sparse comparative data for other forms of CM. Moreover, social care provision for children who experience CM is poorly understood, with limited insights into how needs evolve beyond childhood, including the provision of adequate support and therapeutic interventions during key life transitions such as entering the educational system, the labour market, and parenthood.

Advancing expertise and driving innovation requires comprehensive data collection and analysis on CM and its associated health, social and economic effects [13, 14]. Multi-country collaboration, with data-sharing and expert networks across multiple sectors and informants - including adult survivors of CM (ASCM) - is essential to address challenges such as the low numbers of identified individuals in administrative registries, inconsistent definitions of CM across sectors and countries, differences in perspectives between professionals and individuals with lived experience, varying data collection practices, limited national guidelines and training, and restricted systematic data linkage [15–18]. Consequently, our understanding of European HSC service provision for CM, including disparities and gaps in access, and long-term effects and service needs, is incomplete, emphasising the need for an expanded surveillance programmes to inform evidence-based policy and practice [3].

Building upon the outcomes and expertise developed through the pan-European initiative Euro-CAN COST Action 19106 (www.euro-can.org)—which laid the groundwork for the SERENA project (Assessing and improving access to health and social care SErvices for children RENdered vulnerable by Abuse)—this project will undertake an early life course approach to identify upstream opportunities and the settings where interventions can be targeted. By doing so, we aim to improve HSC trajectories, support transitions across developmental stages and improve long-term health and wellbeing outcomes for children who experienced CM. SERENA will undertake a critical assessment of current HSC service pathways in multiple European countries. By leveraging in-depth, cross-sectoral data collection and linkage, and incorporating the lived experiences of ASCM, SERENA seeks to identify key structural and procedural barriers to service access, both prior to and following the formal recognition of CM. The overarching aim of SERENA is to enhance access to effective, timely, and contextually appropriate HSC services for individuals impacted by CM in Europe. To this end, the project will generate a set of evidence-based, actionable recommendations spanning childhood and early adulthood life stages at the sectoral, national, and European levels. These recommendations will inform improvements in early detection, the optimisation of care pathways, and ultimately contribute to improved short- and long-term outcomes for affected individuals, based on the rigorous analysis of the consequences of CM during childhood, adolescence and early adulthood, alongside an estimation of its societal and economic burden.

SERENA is a large-scale research initiative funded by Horizon Europe, designed to enrich the current body of knowledge regarding CM and the role of HSC services and improve evidence-informed practices. The project comprises 22 partners from multiple European countries and operates within the Horizon Europe framework, with governance based in France. Using multi-country, multi-sectoral, mixed methods, and a longitudinal design, SERENA aims to provide evidence-based recommendations for HSC professionals and policymakers to enhance CM detection and optimise the planning and delivery of HSC services. The project’s novelty is its comprehensive approach, as the recommendations will: (1) be based on a European-wide project on HSC access and barriers for maltreated children; (2) draw on both quantitative and qualitative data from multiple countries; (3) include an economic evaluation of the societal costs of CM; (4) be developed through a participatory process involving key stakeholders including ASCM; and (5) be tailored to national, sector-specific, and European level contexts, including guidance on capacity building and training to improve both short- and long-term outcomes for children affected by CM.

Epidemiological studies indicate a lack of research on assessing and improving access to HSC services for maltreated children, which affects decision-making, policy, and practice in child welfare and child protection services [29]. There is a lack of longitudinal, national, register-based studies on CM and HSC utilisation in low and middle-income countries. Even in high-income settings, longitudinal evidence remains scarce [29]. Our novel approach comprises a multi-country, cross-sectoral, mixed methods design which combines longitudinal administrative HSC data, qualitative case studies, and cross-national aggregated child protection data. This facilitates the generation of comprehensive insights into HSC utilisation and barriers to accessing services and addresses several gaps in the evidence. An additional strength is the use of administrative HSC data, enabling analysis of pooled individual level and cross-sectoral data across countries. This real-world project will utilise nationwide data from several European countries, allowing large-scale examination of CM and HSC services with sufficient numbers of recorded children with CM for robust outcome analyses.

SERENA will conduct a multinational longitudinal retrospective cohort study using social- and health care linked registry data. The inclusion of longitudinal data, covering a period of up to 10 years or more, with a recorded timing of maltreatment event will provide valuable insights into early life trajectories of affected children, enhancing our understanding of how experiences during potentially sensitive developmental periods can influence pathways in health and wellbeing.

This design addresses a notable gap in the literature, as most studies on maltreated children’s health rely on retrospective surveys of adults with medical conditions, which are prone to recall bias and false negatives [7, 30]. Longitudinal studies using administrative data can overcome these limitations [7]. In our longitudinal study of pathways through services for maltreated children in care, we will link individual level social care data from Denmark and Wales with demographic, health, education and justice sectors data. This will allow us to map children’s trajectories through HSC systems, analyse transitions between systems, and identify patterns and barriers to access to HSC services. We will supplement this analysis with the ROCKWOOL-Duke Global Child Welfare Database, which aggregates harmonised data from child welfare and statistical agencies across 26 European countries. Before the submission of this European SERENA project, most longitudinal CM studies were US-based.

Compared to using siloed databases to explore HSC responses to CM, our use of cross-sectoral administrative data linkage enables us to account for the way multiple interacting factors influence outcomes across critical periods in people’s lives [27] and to systematically examine population-level responses to CM across multiple and overlapping domains [31, 32]. The participation of ASCM and HSC professionals further ensures that evidence and recommendations cut across systems and reflect people’s lived experiences [27]. In these ways, our approach advances methodological practices in cross-sectoral life course research in Europe and supports efforts to redesign systems that improve health and wellbeing trajectories across the lifespan [4].

SERENA has limitations. Cultural perceptions of CM may lead to different understandings of the qualitative interview questions. There may be challenges with reporting abuse-related service experiences due to stigma and recall issues. We will attempt to mitigate these issues through the use of trained and experienced interviewers and multiple participant recruitment strategies. In the quantitative data, national variations in coding practices for CM types will be addressed by applying algorithms for physical abuse from a previous multinational European study [10] and by developing new algorithms for other types of abuse that account for cultural differences in definitions and recording.

Exposure misclassification due to under-reporting and under-identification of all types of CM will be a feature of administrative data from all sectors, likely leading to an underestimation of the true prevalence. In addition, medico-administrative data captures data on the children most severely affected by CM, representing the “tip of the iceberg” of the phenomenon. While this may limit generalisability to the broader population, our intention in identifying early life course HSC pathways and outcomes for children who experience CM is to help understand the downstream and later life consequences of CM and discuss the effects of access or barriers to HSC services. We will combine our insights with the economic evaluation to recommend upstream policy and practice changes that support effective allocation of our collective resources to benefit children and young people who experience all forms of CM and who have contact with our HSC services [33].

Aligned to this objective and in recognition of the specific limitations of medico-administrative data, we will link social care data with health data. This will make it possible to identify children involved with social care services who have not been to hospital, and to study the care pathways of children identified by either sector. Given that a large proportion of CM-affected individuals are not reported to child protection services [34], some misclassification should still be expected. However, by pooling individual level data across several European countries, SERENA enables the study of CM in one of the largest populations to date. This increases statistical power and makes it possible to detect associations that may previously have gone undetected. To further minimise bias and improve representativeness and interpretive robustness, findings will be synthesised with qualitative results and reviewed by HSC professionals and ASCM stakeholders, who can also recommend additional analyses. Another limitation is that the algorithms used to identify CM types do not explicitly capture the timing or frequency of maltreatment. CM often occurs covertly and may go undetected for long periods, if identified at all. However, the fact that SERENA exploits the databases’ capacity to link healthcare episodes over time on an individual level will enable the identification of recurrent events and patterns among identified children, offering unique insights into recurrence and potential cumulative harm. Nevertheless, the data remains limited to the subset of children identified through HSC administrative data.

System-level challenges in the identification and response to CM may result from limited training among health professionals [32], uncertainty about legal procedures, and concerns about the consequences of misreporting [35]. Coordination and information-sharing across HSC services and judicial systems can be complex and fragmented [17, 36], potentially hindering timely and effective responses.

Moreover, the recognition of maltreatment does not necessarily ensure quick access to support [32], due to potential workforce shortages and long waiting times for mental health services. While these challenges are well recognised in the field, they have received limited attention in cross-sectoral and multinational research. SERENA may be in a unique position to address these gaps by examining barriers to identify maltreatment and access care from both quantitative and qualitative perspectives.

SERENA will advance the state-of-the-art in the field of CM by generating robust, multi-country evidence regarding CM and related use of HSC services across Europe. The project’s cross-sectoral and mixed methods approach should considerably improve our understanding of the barriers to service access, allow us to estimate the societal costs of CM and prioritise future actions informed by lived experience and professional expertise.

Our findings will support evidence-based recommendations for early detection, improved service pathways, and policy development on national and European levels. These recommendations will aim to strengthen HSC system responses, promote cross-sector collaboration, and ultimately to improve outcomes for maltreated children and society at large.

Importantly, the evidence generated by SERENA is designed to be transferable beyond Europe, providing insights and methodological frameworks that can inform policy and practice globally, across different economic settings.