The power of powerful others: health locus of control and vaccination behavior in rural Namibian pastoralists

BACKGROUND: Who we believe controls our health, whether it is ourselves, chance, or powerful others, shapes how we make healthcare decisions. The health locus of control (HLC) framework has been key to understanding self-efficacy in healthcare behaviors. Health promotion often emphasizes self-efficacy in decision-making. However, in more traditional, subsistence based societies with low levels of market integration (the shift from traditional subsistence towards reliance on market-based consumption) self-efficacy may not be sufficient to understand health decisions. This is particularly true with regard to vaccine beliefs and behaviors, where evidence for the role of HLC is mixed, and in populations where entities associated with vaccines may be viewed with suspicion. METHODS: Using a novel ranking task, we examined the association between HLC and vaccine interest and perceptions in Namibian agro-pastoralists (N = 293) across a spectrum of market integration. Market integration was estimated via a principal components analysis. Sets of Bayesian multi-level models were used to assess HLC on vaccination questions via a monotonic function. RESULTS: External HLC dominated: powerful others (e.g., 'doctors') and God domains were ranked highest, while internal HLC ('self') was consistently lowest. Greater market integration was associated with higher internal HLC and lower powerful others HLC. Individuals who ranked 'doctor' highly expressed more pro-vaccine sentiments, whereas those who ranked 'self' highly were more skeptical of vaccines. No HLC ranks predicted COVID-19 vaccination status. CONCLUSIONS: Variation in HLC across levels of market integration suggests that exposure to broader economic and cultural systems shifts beliefs about health control, with external sources of control playing a more dominant role in more rural areas. In contrast to studies of HLC in industrialized populations, internal HCL was negatively associated with interest and perceptions of vaccine safety. Public health efforts that emphasize individual decision-making may not resonate as well in such contexts, whereas carefully considering the role of powerful others may improve outreach efforts.