The Vaccine Base was found by Carlos Oliveira for creating the Vaccine to cure Jill Valentine of the t-Virus infection. Being the vaccine base, it was likely a non-contaminated sample of the t-virus. This item can be found in the Room 402 after solving the "hospital shelf" puzzle. The picture of Arklay Mountains, hanging on the wall will fall and the locked safe can be reached after solving the puzzle. The passcode can be found in the Room 401. Exploring the locked safe, Carlos can read next message: "It's locked with a number-based lock.". After picking it up, the message can be read in the empty safe "Nothing more.".