Likely Simian Virus Contamination of Millions of Polio Vaccine Doses From 1963 - 81

More bad news regarding polio vaccines: a Cold-war era polio vaccine, manufactured and distributed by the Soviet Union, could have infected millions of recipients with SV40, a simian (monkey) virus. That virus has been linked with a form of human lung cancer called mesothelioma.

Apparently the Soviet Union's method of eliminating the SV40 virus from their vaccine seed stocks -- which used monkey cells as the poliovirus growth medium -- only killed 95% of SV40 contamination. Besides millions who received the vaccine in Eastern Europe, China, Japan and at least several African nations, between 10 and 30 million Americans may have received an SV40-contaminated dose of polio vaccine. The US FDA is reportedly being sued for the alleged cancer connection (though mesothelioma is most often associated with asbestos exposure).

So, if there is any "conspiracy" in the international polio vaccine program, it appears the Soviet Union -- not the USA -- is the suspect. But what was the US Government doing, in the middle of the Cold War, giving Soviet-made vaccine to US citizens?