Shedding and Contamination Concerns in Immunization Products  

While health authorities often assert that immunization products do not shed or pose risks to others, some critics argue otherwise. They claim that certain formulations especially live attenuated types can release viral or bacterial particles, potentially mutating and increasing virulence. Cases like pertussis and Gardasil are cited as examples, with FDA documents acknowledging concerns before approval. Contamination is another issue raised, as complex production processes using animal tissues and fetal cells may introduce biological material that is difficult to detect or fully remove. Critics argue that these risks are downplayed, despite evidence suggesting unresolved safety challenges, particularly regarding immune reactions and long-term effects.