RSV is caused by contaminated polio vaccines

"Another important consideration in attempts to eradicate poliomyelitis by vaccination is the contamination of polio vaccines by chimpanzee coryza virus, renamed respiratory syncytial virus (RSV)." https://www.bmj.com/content/344/bmj.e2398/rr/599724

"It is no secret that the source of RSV is the contaminated polio vaccines in both developing and developed countries." https://medicalveritas.org/contamination-of-polio-vaccines/