Because of limited vaccine supplies and the danger posed by widespread influenza activity in California, the California Department of Health Care Services (DHCS) has temporarily suspended a state law that prohibits the use of flu vaccine containing thimerosal on pregnant women and children under the age of three. The law allows DHCS to issue such exemptions when there are insufficient supplies of thimerosal-free influenza vaccine. The exemption will remain in effect until June 30, 2013.

During this exemption period, physicians should prioritize any remaining supplies of thimerosal-free vaccine for young children and pregnant women when feasible, as long as prioritization does not prevent the immunization of others.

The California Medical Association asked DHCS to explore the need for an exemption after hearing reports of shortages from the American Academy of Pediatrics; who in turn urged DHCS to issue the exemption to help protect young children and pregnant women at high-risk for severe influenza complications.

California’s Mercury-Free Act took effect on July 1, 2006. Under the law the mercury limit for influenza vaccine is 1 microgram per 0.5 milliliters. Thimerosal is a mercury-containing preservative used in some vaccines since the 1930's. There is no documented scientific evidence of harm caused by the low doses of preservative in vaccines, except for minor reactions like redness and swelling at the injection site.

For more information regarding the exemption, please review the California Department of Public Health’s (CDPH) letter to interested parties.

Questions on the exemption should be directed to the CDPH Immunization Branch at (510) 620-3737.