Taken from the NATIONAL VACCINE INFORMATION CENTER newsletter:

A word of caution: Yes this flu vaccine contains potentially harmful levels of mercury - especially in younger children, babies and lightweight adults. However, if one has a severely depleted immune system [immunocompromised], the benefits likely outweigh the risks. Ask your doctor.

Key points:

• It is of interest to note that the EPA considers any material that has greater than 200 ppb of mercury to be hazardous waste. The flu vaccine, as well as tetanus booster, has thimerosal levels that exceed this value by 250 times or 50,000 ppb mercury.
• Giving a 3 yr old child the flu vaccine will raise their blood level of organic mercury beyond what the CDC has defined as a chemical poisoning.
• The current flu vaccine will deliver a dose of organic mercury to a 3 year old that meets the definition of a chemical poisoning by the MMWR, CDC and HHS. Furthermore, the recommended schedule requires that this dosebe given twice (one month apart).
• A 125 pound teenager or adult, who gets a recommended flu and meningococcal vaccination, could be 4-8 times over the EPA limit for a single mercury exposure, depending upon the manufacturers. A teen or adult who got a mercury-containing flu vaccine would have to weigh 551 pounds to be under the EPA limit for a single mercury exposure.
• The Manufacturer's inserts, the package labeling, do not address nor do they warn about the dangerous levels of organic mercury being given.