Ancillary care responsibilities in observational research: Field reflections from a high-endemic malaria area in the Democratic Republic of the Congo

Large-scale household surveys in resource-constrained, high-disease-burden settings expose health needs that fall outside study protocols, raising questions about researchers’ ancillary care obligations. Drawing on empirical experiences from SEMA ReACT, a hybrid effectiveness-implementation study assessing community-based pre-referral treatment of severe malaria in children aged 6 months to 5 years in Kapolowe, Democratic Republic of Congo, we examine ethical tensions at the research-health system interface and consider their implications for research ethics and health systems practice. During surveys, field teams encountered clusters in which most sampled children tested positive for malaria. Although sampling followed a predefined, ethically approved protocol, researchers also observed nearby non-sampled children with possible illness. These encounters highlighted tensions between protocol adherence, resources and responses to unmet health needs in communities with limited access to care. We argue that current ethics guidelines provide insufficient direction, leading to inconsistent responses that shift responsibility onto frontline researchers rather than embedding it within study design, funding, and ethical review. In settings characterized by weak health systems and unmet healthcare needs, strict adherence to sampling boundaries may inadvertently reinforce inequities and undermine community trust. Observational research further blurs the distinction between participants and non-participants, as researchers become visible health actors approached for assistance by community members. Grounded in ancillary care frameworks and theories of global justice, we propose a limited but affirmative obligation for researchers to address acute, serious health conditions encountered during fieldwork, extending under defined circumstances to similarly situated non-participants. Such obligations should be prospectively addressed through explicit planning, resource allocation, referral mechanisms and ethics oversight to ensure responses are equitable, feasible, and sustainable. Embedding ancillary care considerations prospectively strengthens ethical integrity, promotes trust, and enhances the social value of global health research.