>In light of the biological evidence supporting the theory that SV40-contamination of polio vaccines could contribute to human cancers, the committee recommends

>In light of the biological evidence supporting the theory that SV40-contamination of polio vaccines could contribute to human cancers, the committee recommends continued public health attention in the form of policy analysis, communication, and targeted biological research. Come on – this is just the standard ass-covering language in a scientific paper. "Further research is needed." By the nature of the case it's very hard to conclusively show that no-one has ever had a cancer caused by a 1960s Polio vaccine. But at present there is no good evidence that this has happened, as the paper that you linked to states very clearly. Any medication can contain contaminants. I do not understand why you think that the mere abstract possibility that any given vaccine might contain contaminants is relevant to COVID vaccination efforts. This is like cautioning against people taking Aspirin because any given Aspirin pill might contain contaminants.