Thimerosal is commonly used as an antiseptic/preservative in vaccines in the range of 1:10,000 to 1:20,000. Welsh's and Hunter's 1940 findings, applied to current thimerosal use in vaccines, lead to the conclusion that thimerosal completely inhibits phagocytosis in blood, one of the body's most vital immune defenses!

What Every Parent Should Know about Childhood Immunization (ed. 1993)