## 4 Discussion
### Strengths, Limitations, and Future Research Opportunities  
Our realist and grounded theory-building approach allowed enhanced data validity and reliability. Data were collected and analyzed in practice, in real-life settings. In this study, we collected qualitative data on a CHW support program in the context of the city of Ghent during the COVID-19 pandemic. Since controlling the variables is not possible when studying complex social problems, it is important to know as much as possible about the variable in which the supposed key mechanisms function. Therefore, keen documentation of the context in which the mechanism is trigged is required, and this is preferably repeated in differing contexts and circumstances. Although the selection of the cases and the interviewees of interest has been done with respect to this principle, problems according to the generalizability of the findings could still arise. The context of the COVID-19 pandemic in this study could possibly impact the generalizability of our findings since these circumstances themselves could already influence the process of building trust between CHWs and clients. Possibly, clients were more suspicious towards volunteers in these challenging times with anxiety prevailing, or, by contrast, clients may be more eager to trust volunteers in times of social isolation. Further research in other--non-COVID--contexts is needed to examine whether this theory can be consolidated.  
Another limitation of this study could be the strong involvement of the researcher [PERSON] in the program, which could risk assumptions being made beforehand. To overcome this, the data were triangulated with the two other researchers, [PERSON] and [PERSON].  
One of this study's main strengths, namely the program theory being partly grounded in data and not solely the result of a theoretical exercise, has generated some limitations as well. Our program theory reflects the idea that context elements at the micro-level (adopting a client-centered attitude, coordination, temporariness, and link with primary care practice) indeed play a huge role as a catalyzer for key mechanisms. However, the \"upstream\" social determinants of health, such as social disadvantage, risk exposure, and structural inequities, also play a fundamental role. Context elements at meso- (organization, network, partnerships, local politics,... ) and macro-level (policy, law, regulation,...) may trigger or impede important context elements at the micro-level. Therefore, more attention is needed for the cascade of context factors at the structural (political and societal) level allowing (or impeding) these mechanisms.  
In this study, the lack of affiliation with an institution and the status of a CHW as a non-professional healthcare provider increases the building of trust with community members. However, it is also important to explore CHWs' role in relation to other health workforce and to integrate CHW interventions into the general health and community system [14]. Through their specific backgrounds and interactions with community members, CHWs develop expert knowledge, a nuanced health 'intelligence' that risks being lost when not integrated into the primary care team. Unfortunately, strategies that elaborate on systemsof CHWs allowing community members' needs and visions to be actively involved in the organization and operation of PCP remain scarce. This points to the need for co-creation of knowledge and for active involvement of communities, which has not yet been constructed. This is an ambition for the future.