Affiliation of authors: R. A. Vilchez (Departments of Medicine and Molecular Virology and Microbiology), A. S. Arrington, J. S. Butel (Department of Molecular Virology and Microbiology), Baylor College of Medicine, Houston, TX.
Correspondence to: Regis A. Vilchez, MD, Department of Medicine, Section of Infectious Diseases, One Baylor Plaza, BCM-286, Rm. N1319, Houston, TX 77030 (e-mail: rvilchez{at}bcm.tmc.edu).
We read with interest the recent article by Engels et al. (1) in which the authors performed a retrospective birth-cohort analysis in Denmark following exposure to poliovirus vaccine contaminated with simian virus 40 (SV40) to clarify whether SV40 infection increases risk of mesothelioma, choroid plexus tumors, and non-Hodgkins lymphoma, or of cancers arising in children. The authors concluded that "exposure to SV40-contaminated poliovirus vaccine in Denmark was not associated with increased cancer incidence."
It is important to point out that several limitations have been recognized for this and similar epidemiologic studies addressing exposure to SV40-contaminated poliovirus vaccines and the incidence of human cancers (Table 1) (24). Indeed, an evaluation by the Institute of Medicine Immunization and Safety Review Committee found that the epidemiologic data used in birth-cohort studies to examine cancer rates in individuals potentially exposed to SV40-contaminated vaccines are inadequate to evaluate a causal relationship (2). The validity of observational studies, such as the retrospective analyses by Engels et al. (1), depends on the accuracy of the existing knowledge of the biologic properties of SV40 and the identification of the human population infected with the virus (2,4,5). Therefore, supportive evidence from experimental studies is required to draw causal inferences in human disease (4,6). Indeed, a recent casecontrol study (5) of 1793 cancer patients indicated that there is a statistically significant excess risk of SV40 associated with primary brain cancers (odds ratio [OR] = 3.8, 95% confidence interval [CI] = 2.6 to 5.7), primary bone cancers (OR = 24.5, 95% CI = 6.8 to 87.9), malignant mesothelioma (OR = 15.1, 95% CI = 9.2 to 25.0), and non-Hodgkins lymphoma (OR = 5.4, 95% CI = 3.1 to 9.3).
|
NOTES
R. A. Vilchez is the recipient of the 2001 Junior Faculty Development Award from GlaxoSmithKline and the 2002 Translational Research Award from the Leukemia and Lymphoma Society.
References
1 Engels EA, Katki HA, Nielsen NM, Winther JF, Hjalgrim H, Gjerris F, et al. Cancer incidence in Denmark following exposure to poliovirus vaccine contaminated with simian virus 40. J Natl Cancer Inst
2003;95:5329.
2 Stratton K, Almario DA, McCormick MC. SV40 contamination of polio vaccine and cancer. Immunization Safety Review Committee, Board of Health Promotion and Disease Prevention, Institute of Medicine of the National Academies. Washington (DC): The National Academies Press; 2002.
3 Rollison DE, Shah KV. The epidemiology of SV40 infection due to contaminated polio vaccines: relation of the virus to human cancer. In: Khalili K, Stoner GL, editors. Human polyomaviruses: molecular and clinical perspectives. New York (NY): Wiley-Liss; 2001. p. 56184.
4 Vilchez RA, Kozinetz CA, Butel JS. Conventional epidemiology and the link of SV40 infections with human cancers. Lancet Oncol 2003;4:18891.[CrossRef][ISI][Medline]
5 Vilchez RA, Kozinetz CA, Arrington AS, Madden CR, Butel JS. Simian virus 40 in human cancers. Am J Med 2003;114:67584.[CrossRef][ISI][Medline]
6 Fredericks DN, Relman DA. Sequence-based identification of microbial pathogens: a reconsideration of Kochs postulates. Clin Microbiol Rev 1996;9:1833.[Abstract]
![]() |
||||
|
Oxford University Press Privacy Policy and Legal Statement |