A return to current recommendations is anticipated as soon as adequate supplies of thimerosal-free vaccines are available. The AAP and the CDC have been developing guidance materials for their constituents.
Thimerosal constains a small amount of mercury in the form of ethyl mercury.
The large risks of not vaccinating children far outweigh the unknown and probably much smaller risk, if any, of cumulative exposure to thimerosal-containing vaccines over the first six months of life. There are no guidelines for ethyl mercury, but experts agree that methyl mercury guidelines are appropriate to use in this situation. There is a significant safety margin incorporated into all Federal guidelines on methyl mercury exposure. There is no evidence of any harm caused by the level of exposure that some children may have encountered in following the existing immunization schedule. The Public Health Service, the American Academy of Pediatrics, and vaccine manufacturers agree that the use of thimerosal as a preservative should be removed as soon as possible.