Abstract
Virtual health communities have become popular social environments where patients and carers are able to receive advice and support from other members of the community. However, not much is known of factors that influence willingness to share personal health information. Using the resource exchange theory and the affect theory of social exchange, this paper examines the role of social capital, gratitude and indebtedness in explaining levels of willingness to reciprocate in virtual health communities. Data was collected from 361 users of virtual health community sites in a cross-sectional survey conducted in Gauteng, South Africa. Structural equation modelling was used to analyse the data. The findings show that willingness to reciprocate is directly influenced by social capital, emotions of gratitude and indebtedness. The results also show that gratitude and indebtedness mediate the influence of social capital on willingness to reciprocate. The findings can be used by managers of virtual health communities to inform strategies aimed at stimulating more knowledge sharing on their sites.