Hybrid effectiveness-implementation studies in infection prevention and infectious diseases: a narrative review

Hybrid effectiveness-implementation studies simultaneously assess clinical effectiveness and implementation, thereby accelerating the translation of research into healthcare practice. Such designs are relevant in infection prevention and control (IPC) and infectious diseases (ID), where research-informed interventions frequently face barriers to real-world adoption, implementation, and sustainment. Implementation science offers methods and frameworks to bridge this research-to-practice gap, but the application of hybrid studies remains limited in IPC/ID.

This narrative review aims to give an overview and characterize the use of hybrid effectiveness-implementation studies in IPC and ID research by identifying hybrid studies and protocols, analysing IPC/ID interventions and implementation strategies employed, summarizing implementation and effectiveness outcomes reported, and identifying gaps and opportunities for advancing the field.

We systematically searched Medline, Embase, CINAHL, Cochrane, and Clinicaltrials.gov to identify study reports, study protocols, and trial registries published in English, addressing both implementation and clinical effectiveness of IPC/ID interventions in acute inpatient settings.

Twenty-six hybrid effectiveness-implementation studies were included, predominantly from high-income countries. The studies commonly evaluated effectiveness outcomes such as patient safety, service efficiency, and patient mortality. Frequently reported implementation outcomes included intervention and implementation fidelity, acceptability, adoption and feasibility, and implementation determinants (barriers and facilitators). Diverse conceptual theories, models, and frameworks from implementation science were employed. We identified opportunities for improving hybrid study reporting, including inconsistent labelling of hybrid methods, conceptual overlap between effectiveness and implementation outcomes, particularly fidelity, and fragmented reporting practices separating clinical effectiveness and implementation results.

Improving and standardizing reporting of hybrid studies, and expanding hybrid studies to diverse geographical and resource settings could substantially enhance the impact of IPC/ID interventions. Clearer distinction and labelling of hybrid designs and increased methodological rigour would improve comparability across studies, facilitating broader learning and greater real-world applicability of IPC/ID research.