When the order indicates the first immunization administration should occur. Active dateTime is most often used to specify immunizations for which administration is intended at a specific time in the future. If Active dateTime is not specified, it defaults to the Author (signed) dateTime.
A statement that asserts the value of a property (observable) of the subject. The subject is often the patient, but may be a condition, a physical structure, or another clinical statement. For example, an interpretation is a finding about an observation.