As a result of this study, we specified 17 health domain challenges that can be categorized into four groups: (i) meeting regulatory requirements and public health surveillance, (ii) ensuring security and privacy, (iii) ensuring interoperability, and (iv) preventing waste of resources.
The MLR consists of 78 sources of formal literature and 23 sources of gray literature from 2016 to 2021. We focused on understanding to what degree blockchain could answer the challenges inherited in the health domain and whether blockchain technology may bring new challenges to health applications. Noticing that blockchain technology is rapidly growing, we extended the previous SLR with a multivocal literature review (MLR) approach to present the state of the art in this study. The previous SLR included 27 formal literature papers from 2016 to 2020. Previously, we performed a systematic literature review (SLR) to explore how blockchain technology potentially benefits health domain applications. Each new technology, however, comes with its challenges alongside its opportunities. It provides a resilient and secure platform for modifications due to its distributed and shared nature and cryptographic functions. Blockchain technology has been changing the nature of several businesses, from supply chain management to electronic record management systems and copyright management to healthcare applications.