We determined that the procedure used by this manufacturer to inactivate SV40 in oral poliovirus vaccine seed stocks based on heat inactivation in the presence of MgCl2 did not completely inactivate SV40. These SV40-contaminated vaccines were produced from early 1960s to about 1978 and were used throughout the world. Our findings underscore the potential risks of using primary monkey cells for preparing poliovirus vaccines, because of the possible contamination with SV40 or other monkey viruses, and emphasize the importance of using well-characterized cell substrates that are free from adventitious agents.
This story is not new – many of of us who thoroughly researched the vaccination issue before choosing whether or not to immunize were already aware of this fact years ago.
I became aware of the tainted polio vaccines from 1955-1963 in the late 1990′s and it was one of the primary motivators for me to choose a “no shots, no way” approach for my children.
What is new is that the CDC is finally admitting it.
What took you so long CDC? Many of the folks vaccinated with the tainted polio stock are already dead from cancer with many more getting diagnosed each and every day! (source)