© 2021 IEEE.Traditional medical systems are vulnerable to attacks, leaks, and loss of data. The centralized structure of medical systems makes them more susceptible to attacks. Blockchain can be used as a solution to this issue. In particular, using blockchain to track patient medical history and vaccination records can guarantee privacy and security, which are critical requirements for healthcare systems. In this paper, we propose a blockchain-based application to maintain and share medical data and vaccination records using Hyperledger Fabric and Ethereum platforms to ensure data integrity and immutability. Our vaccination tracking system based on the Ethereum platform allows easy verification for people who want to travel abroad. For this system, we employ Ganache to test these vaccination records in a safe and deterministic environment. We have evaluated the performance of our implementation using Hyperledger Caliper and Explorer. The results show that our blockchain-based systems can increase the efficiency and transparency of tracking medical and vaccination records. We believe our proposal is especially valuable in the context of the ongoing COVID-19 pandemic because it providesa secure way to update, share and verify vaccination records.