Vaccine contamination with SV40

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Vaccine contamination with SV40 occurred in the United States and other countries between 1955 and 1961.

Simian vacuolating virus 40, known as SV40, is a virus found in monkeys and humans, which has the potential to cause cancer, in animals and humans.[1] Soon after its discovery, SV40 was identified in early batches of the oral form of the polio vaccine. The vaccines in which SV40 was found, were produced between 1955 and 1961 by Lederle (now a subsidiary of Wyeth). The contamination may have been in the original seed strain (coded SOM) or in the substrate—primary kidney cells from infected monkeys used to grow the vaccine virus during production.

Both the Sabin vaccine (oral, live virus) and the Salk vaccine (injectable, killed virus) were affected; the technique used to inactivate the polio virus in the Salk vaccine, by means of formaldehyde, did not reliably kill SV40. The contaminated vaccine continued to be distributed to the public through 1963.[2][3]

It was difficult to detect small quantities of virus until the advent of polymerase chain reaction; since then, stored samples of vaccine made after 1962 have tested negative for SV40. In 1997, Herbert Ratner of Oak Park, Illinois, gave some vials of 1955 Salk vaccine to researcher Michele Carbone.[4] Ratner, the Health Commissioner of Oak Park at the time the Salk vaccine was introduced, had kept these vials of vaccine in a refrigerator for over forty years.[5][better source needed] Upon testing this vaccine, Carbone discovered that it contained not only the SV40 strain already known to have been in the Salk vaccine (containing two 72-bp enhancers) but also the same slow-growing SV40 strain currently found in some malignant tumors and lymphomas (containing one 72-bp enhancer).[6] It is unknown how widespread the virus was among humans before the 1950s, though one study found that 12% of a sample of German medical students in 1952 – prior to the advent of the vaccines – had SV40 antibodies.[7]

An analysis presented at the Vaccine Cell Substrate Conference in 2004[8][medical citation needed] suggested that vaccines used in the former Soviet bloc countries, China, Japan, and Africa, could have been contaminated up to 1980, meaning that hundreds of millions more could have been exposed to the virus unknowingly.

Population level studies show no evidence of any increase in cancer incidence as a result of exposure,[9] though SV40 has been extensively studied.[10] A thirty-five year followup found no excess of the cancers commonly associated with SV40.[11]


  1. ^ Schipani, Vanessa (24 Apr 2018). "Did the Polio Vaccine Cause Cancer?". Retrieved 4 Mar 2020.
  2. ^ CDC website Accessed 1 November 20166
  3. ^ Study Is Unsure on Tainted Polio Vaccine's Cancer Role. Denise Grady. New York Times. October 23, 2002 Accessed 1 November 2016
  4. ^ Ferber, Dan (2002). "Virology. Monkey virus link to cancer grows stronger". Science. 296 (5570): 1012–1015. doi:10.1126/science.296.5570.1012. PMID 12004103. S2CID 32723346.
  5. ^ Bookchin, Debbie; Schumacher, Jim (2004). The Virus and the Vaccine. St. Martin's Press. pp. 226–28. ISBN 978-0-312-27872-4.
  6. ^ Rizzo, Paola; Di Resta, Ilaria; Powers, Amy; Ratner, Herbert; Carbone, Michele (1999). "Unique Strains of SV40 in Commercial Poliovaccines from 1955 Not Readily Identifiable with Current Testing for SV40 Infection". Cancer Research. 59 (24): 6103–8. PMID 10626798.
  7. ^ Martini, F; Corallini, A; Balatti, V; Sabbioni, S; Pancaldi, C; Tognon, M (9 July 2007). "Simian virus 40 in humans". Infectious Agents and Cancer. 2: 13. doi:10.1186/1750-9378-2-13. PMC 1941725. PMID 17620119.
  8. ^ Bookchin, Debbie (7 July 2004). "Vaccine scandal revives cancer fear". New Scientist.
  9. ^ NIH/National Cancer Institute (2004-08-25). "Studies Find No Evidence That Simian Virus 40 Is Related To Human Cancer". Science Daily.
  10. ^ Hilleman MR (1998). "Discovery of simian virus 40 (SV40) and its relationship to poliomyelitis virus vaccines". Dev Biol Stand. 94: 183–90. PMID 9776239.
  11. ^ Carroll-Pankhurst, C; Engels, EA; Strickler, HD; Goedert, JJ; Wagner, J; Mortimer EA Jr. (November 2001). "Thirty-five year mortality following receipt of SV40- contaminated polio vaccine during the neonatal period". Br J Cancer. 85 (9): 1295–7. doi:10.1054/bjoc.2001.2065. PMC 2375249. PMID 11720463.