### Question
How does the law define significant aggravation?


### Answer
Under *42 U.S.C. § 300aa*, **significant aggravation** is defined as:

> any change for the worse in a preexisting condition which results in markedly greater disability, pain, or illness accompanied by substantial deterioration of health

#### Citation:
  - *42 U.S.C. § 300aa*
  - Heading: **CHAPTER 6A-PUBLIC HEALTH SERVICE > SUBCHAPTER XIX-VACCINES > Part 2-National Vaccine Injury Compensation Program > subpart d-general provisions**

