Thiomersal und Na-timerfonat were used since more than 7 decades as preservatives in vaccines and other biologicals. The wide-spread use has brought up concern considering their irreversible neurotoxic, teratogeneous, nephrotoxic and allergenic properties. In Austria in 1988 discussion started concerning the ban of organomercurials in biologicals. However, it lasted until 1999 that EMEA, the FDA and the WHO uniformly claimed for the removal of these compounds from all vaccines as fast as possible.
In Austria the Advisory Committee of Immunization Practices recommended on 4th Oct. 1999 that, wherever possible mercury-free vaccines have to be used. This was issued as a binding decree by the ministry of health. Therefore for the childhood vaccines in the year 2000 only preservative free vaccines were used for the primary vaccination schedule. Additionally, the dT-booster was also mercury-free. With the exception of monovalent HBV-vaccination for newborns of HbsAg positive mothers all children receive mercury free vaccines now in the first decade. In consequence, a decrease of the high sensitization rate against mercury (30% of all eczema patients) can be expected in the future. Furthermore, the burden with potentially neurotoxic substances during the first year of life due to vaccination will be reduced significantly.
Unfortunately thiomersal containing influenza vaccines are still used in great amounts despite the otherwise recommendations. Furthermore, due to the decentralized licensing procedure thiomersal containing vaccines were newly licensed – in contrast to EMEA procedures. It is of note that even manufacturers who managed to produce preservative free vaccines in the early 70ies (e.g. Quinto-Virelon“) stepped back to using mercury containing preservatives, resulting in a discontinuation of a permanent process of improvement of the quality of vaccines.