In preparation for swine-flu vaccinations next month, Washington's Health Department ... temporarily suspended a rule that limits the amount of a mercury preservative [called Thimerosal] in vaccines given to pregnant women and children under the age of 3. Thimerosal has been eliminated from most vaccines in the United States, but it will be added to the bulk of the swine-flu vaccine. A vocal minority believes the compound could be linked to autism. About 15 percent of the vaccine supply will be mercury-free. Thimerosal will be added to the vaccine because it is being produced in vials that contain enough medication for 10 shots. The mercury compound kills bacteria, lowering the risk that the drug will be contaminated by needles used to withdraw separate doses. Every time you introduce a needle, you run a risk of introducing a potential contaminant," said Dr. Tony Marfin, state epidemiologist for infectious disease. Mercury-free vaccine will be produced in single-dose vials. Nasal sprays do not contain mercury but are not recommended for children under the age of 2 and pregnant women, because they contain live, weakened virus. The law limiting the mercury preservative will be suspended for six months and applies only to the swine-flu vaccines. Once common in vaccines, thimerosal has been largely phased out in most wealthy nations. Children's vaccines in the United States are almost exclusively mercury-free, single-dose injections. After 1976's mass vaccination against a different swine-flu strain, about 500 people developed a neurological disorder called Guillain-Barre Syndrome (GBS), and some died. Scientists still haven't figured out why.