Each state or territorial health department is responsible for establishing internal operations and schedules for reporting data. As a result, there are differences among states in the frequency of reporting. Data on doses of vaccine delivered and administered include data received by CDC as of 6:00 am ET on the day of reporting. Vaccination data in CDC’s COVID Data Tracker are updated daily between 1:30 pm and 8:00 pm ET. On federal holidays, updates will occur the following day. Data can be updated on different schedules and reflect data “as of” different dates or times of day. There can be a delay between the time a vaccination record appears in a jurisdictional or federal system and when it is received by CDC.  COVID Data Tracker’s vaccination data typically have a lag time from vaccination data shown on a state’s website. The amount of lag time varies for each state. This can be due to the factors described above, or because a jurisdiction uploads data after the 6:00 am ET reporting cutoff. Healthcare providers are expected to report doses administered to federal, state, territorial, tribal, and local agencies within 72 hours of administration. There are often significant differences between the number of doses distributed and the number of people who are vaccinated. This is due to several factors, including the time it takes for doses delivered to be administered, the time it takes for administered doses to be reported to CDC, and how jurisdictions and federal pharmacy partners manage available vaccine stock to meet local demands.