Skip Navigation Links
Centers for Disease Control and Prevention
 CDC Home Search Health Topics A-Z
NIP header
Family
NIP:
bullet NIP HOME
bullet First time visitor?
bullet About NIP
bullet Data and Statistics
bullet International Efforts
bullet Links to other web sites 
bullet Glossary/ Acronyms 

NIP sub-sites:
bullet ACIP
bullet Flu Vaccine
bullet Immunization Registries
bullet Vaccines for Children Program
bullet CASA (Clinic Assessment Program)
bullet AFIX (Grantee Assessment)
bullet VACMAN
 

NIP Site Search
 
For Immunization Information, call the
CDC-INFO Contact Center:
English and Spanish
800-CDC-INFO
800-232-4636
TTY
888-232-6348

Get Acrobat Reader
Get Adobe Reader
Public NIP Home Health Care Proferssionals Partners Media Informacion en Espanol
 

Vaccine Safety  > Issues of Interest > Thimerosal 
Mercury and Vaccines
(Thimerosal)

FACT SHEET

Contents of this page:


What You Should Know

  • Thimerosal is a preservative which contains a type of mercury called ethylmercury. Thimerosal has been used in some vaccines and other products since the 1930's to help keep them safe by preventing bacterial contamination.

  • The level of mercury exposure from vaccines is low. There is no evidence to suggest that thimerosal in vaccines causes any health problems in children and adults other than minor reactions like swelling at the injection site.

  • In July 1999 the Public Health Service (PHS) agencies and the American Academy of Pediatrics (AAP) recommended that thimerosal be taken out of vaccines as a precautionary measure.

  • All routinely recommended licensed vaccines that are currently being manufactured for children in the U.S. [except some influenza (flu) vaccine and Td (tetanus-diphtheria) vaccines] contain no thimerosal or only trace amounts.

top Top

Additional Facts

  • Mercury is a metal that occurs naturally and is found everywhere in the environment. There are different types of mercury. Thimerosal contains approximately 49% ethylmercury.

  • Measles, mumps, and rubella (MMR), varicella (chickenpox), and inactivated polio vaccine (IPV) have never contained thimerosal.

  • In 2004, a report by The Institutes of Medicine (IOM) concluded that there is no association between autism and vaccines that contain thimerosal as a preservative.

  • Evidence is accumulating of lack of harm resulting from exposure to thimerosal in vaccines.
       
  • A recent study conducted by the National Institute of Allergy and Infectious Diseases (NIAID) concluded that mercury levels in the blood of babies that received vaccines with thimerosal remained well below levels considered acceptable by the EPA. Furthermore, ethylmercury (thimerosal) seems to be removed from the body quickly through the gastrointestinal tract (stools).
       
  • CDC recently conducted a study to see whether there are associations between vaccines containing Thimerosal as a preservative and a wide range of neurodevelopmental disorders. Results found no consistent significant associations. Studies to examine these issues are ongoing.

top Top

For more information

Top of page


National Immunization Program (NIP)
NIP Home | Contact Us | Help | Glossary | About | Accessibility

This page last reviewed and modified on May 18, 2004

   

Department of Health and Human Services
Centers for Disease Control and Prevention
CDC Home
  |  CDC Search  |  CDC Health Topics A-Z