To describe the natural history of a condition or disease. To describe the natural history of a condition or disease. To determine effectiveness or cost effectiveness of treatments/services and/or health care products. To measure or monitor safety and harm. To measure quality of care.
According to the NMSS, attacks or flare-ups of symptoms only qualify as exacerbations if: 1  they occur at least 30 days from an earlier flare-up. 2  symptoms last for 24 hours or longer.
The window period is the time it takes for your body to produce HIV antibodies after you have been exposed to HIV. In more than 97% of people, this period lasts between 2 and 12 weeks. In a very small number of people, the process takes up to 6 months.