[JURIST] Health officials said Wednesday that state laws which prohibit a mercury-based vaccine preservative could impede efforts to fight an avian flu pandemic should an outbreak occur. At a meeting of the US Department of Health and Human Services National Vaccine Advisory Committee (NVAC) [official website], the healthcare officials said that six states have already enacted legislation preventing the use of thimerosal [FDA backgrounder; FAQs], and over 20 states have similar bills pending. Most doctors believe thimerosal is safe, saying it does not affect the body in the same manner as mercury found in pollutants, but several groups disagree and claim that use of the preservative can be linked to neurological diseases including autism. Creating mercury-free vaccines requires packaging individual doses which is expected to pose a major problem if large batches of the vaccine need to be rushed in the event of an avian flu pandemic. Dr. Melinda Wharton of NVAC said that legislators may not understand the ramifications of the new and proposed laws, and claims that the bills were pushed by activists. Earlier this month, President Bush asked Congress to devise a plan to provide liability protection [JURIST report] for vaccine manufacturers to prepare for a possible bird flu epidemic [White House fact sheet]. Reuters has more.