As a footnote, I came across a couple interesting papers on the topic of vaccine contamination from around 2012. They talk about the usual development time bei

As a footnote, I came across a couple interesting papers on the topic of vaccine contamination from around 2012. They talk about the usual development time being 8-10 years, and about a few recent cases of vaccine contamination. Extraneous agent detection in vaccines: https://www.researchgate.net/profile/Attila_Farsang_Dr/publication/224939093_Extraneous_agent_detection_in_vaccines_-_A_review_of_technical_aspects/links/59ea4ba2aca272cddddb7cce/Extraneous-agent-detection-in-vaccines-A-review-of-technical-aspects.pdf https://www.researchgate.net/profile/Attila_Farsang_Dr/publi... Detection of Avian Retroviruses in Vaccines: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647912/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3647912/