Early batches of poliovirus vaccine used in the late 1950s and early 1960s were contaminated with a monkey virus called Simian Virus 40, or SV40. Recently an investigator found proteins made by SV40 virus in unusual tumors in adults. The studies were suggestive enough that the National Institutes of Health continued to research the association. However, subsequent studies have not confirmed the initial observation. Nevertheless, no currently manufactured polio vaccines contain SV40, so current poliovirus vaccines pose no risk of ill effects from the virus. You can read more about vaccine myths in my book God’s Design for the Highly Healthy Child.
Here are other blogs in this series you might find useful: