  Transforming a vaccine concept into a real vaccine product is a complicated
process and includes finding suitable antigens and regulatory, technical, and
manufacturing obstacles. A relevant issue within this scope is the clinical
trial process. Monitoring and ensuring the integrity of trial data using the
traditional system is not always feasible. The search for a vaccine against the
coronavirus SARS-CoV-2 illustrates this situation. The scientific credibility
of findings from several vaccines' clinical trials contributed to distorted
perceptions concerning the benefits and risks of the drug. This scenario is
ideal for applying technologies such as Blockchain and Smart Contracts in
healthcare issues. This paper proposes a protocol based on Smart Contracts,
named VaccSC, to enable transparency, accounting, and confidentiality to Phase
III of vaccine experiments. The protocol was implemented in Solidity language,
and results show that the VaccSC enables double-blindness, randomization, and
the auditability of clinical data, even in the presence of dishonest
participants.
