Thimerosal: What you need to know about vaccine preservative
Thimerosal is best known as a preservative used in some vaccines to keep them from becoming contaminated.
The preservative has gotten a lot of attention over the years, particularly since it was removed from childhood vaccines in 2001.
Several studies have shown that the preservative is safe, but not everyone has been convinced. Here's what you need to know about what it is (and what it isn't).