  In the context of the COVID-19 pandemic, the rapid roll-out of a vaccine and
the implementation of a worldwide immunization campaign is critical, but its
success will depend on the availability of an operational and transparent
distribution chain that can be audited by all relevant stakeholders. In this
paper, we discuss how blockchain technology can be used for assuring the
transparent tracing of COVID-19 vaccine registration, storage and delivery, and
side effects self-reporting. We present such system implementation in which
blockchain technology is used for assuring data integrity and immutability in
case of beneficiary registration for vaccination, eliminating identity thefts
and impersonations. Smart contracts are defined to monitor and track the proper
vaccine distribution conditions against the safe handling rules defined by
vaccine producers enabling the awareness of all network peers. For vaccine
administration, a transparent and tamper-proof side effects self-reporting
solution is provided considering person identification and administrated
vaccine association. A prototype was implemented using the Ethereum test
network, Ropsten, considering the COVID-19 vaccine distribution tracking
conditions. The results obtained for each on-chain operation can be checked and
validated on the Etherscan, demonstrating various aspects of the proposed
system such as immunization actors and safe rules registration, vaccine
tracking, and administration. In terms of throughput and scalability, the
proposed blockchain system shows promising results.
