The vaccine requires two doses. The CDC will send an equal quantity of the 2nd dose to each facility 21-28 days after the 1st dose was sent, depending on the manufacturer. It is expected that all Phase 1A sites will administer both the 1st and 2nd doses to registered individuals. Once in place, the vaccine management information system (VMIS) will support second-dose electronic notifications, such as email and text messages. In addition, sites should have redundant methods in place, such as pre-scheduling appointments for the second dose and pre-planning to host clinics during the second-dose administration timeframe. The federal government will hold back a sufficient supply of vaccine to provide the second dose.