| Age at enrollment | Age Event is the Age at enrollment. In the case of a subject enrolled in multiple studies, this value is the minimum age for all the studies. | | |
| Age at infection | Age Event is the Age at infection. | | |
| Age at initial treatment | Age Event is the Age at initial treatment. | | |
| Age at initial vaccine administration | Age Event is the Age at initial vaccine administration. | | |
| Age at Study Day 0 | Age Event is the Age at Study Day 0. | | |
| Not Specified | Age Event is not specified or not received. If no Age Event value is received, then this is the system default value. | | |
| Other | Age Event is some Other value not in CV Terms. | | |
| Postmenstrual age | Best estimate of the first day of last menstrual period to birth plus time elapsed from day of birth. [def-source: NCI][attr: NICHD] | | |