With respect to (a), Health Canada and external partners have developed the testing methodology for detecting SV40 in cells and tissues from patients with non-Hodgkin lymphoma, NHL, and are currently developing blood tests to detect antibody to simian virus 40 (SV40) to permit our planned studies of the correlation of SV40 infection and certain cancers.
With respect to (b), “A review of relevant literature on Simian Virus 40 published between July 2000 and November 2002: Update to July 2000 Simian Virus 40 paper presenting recent knowledge on the zoonotic aspects of SV40 and any identified relationship to blood safety” was completed in early 2003. The review was aimed to identify research priorities and concluded: No firm link has established SV40 as a cause of human cancer. As in the July 2000 report, more recently published studies continue to show no evidence of a significant increase in rates of cancer linked to SV40. Continued research into SV40 will be important as SV40 may yet prove to be a cofactor in the development of certain types of cancers.
With respect to (c), risk assessment of SV40 for human diseases associated with blood is being done through two approaches:
One, the risk of SV40 for the Canadian blood supply is being assessed through Health Canada’s Rapid Response Surveillance System for Emerging Bloodborne Pathogens, RRSS; RRSS has in place a system which has been activated in response to this issue.
Two the Canadian Blood and Marrow Transplant Group, CBMTG, approach: has stored blood specimens of patients with non-Hodgkin’s lymphomas, NHL, and other conditions who are being studied both retrospectively and prospectively and compared to assess the clinical implications of SV40 in NHL and possibly other malignant conditions, as well as, its transmissibility through blood and blood product transfusion, and organ and tissue transplantation.
Blood specimens from a sample of the general Canadian population and from patients at risk of multiple blood transfusion will be tested for SV40 infection with consent to assess: one, the level of SV40 infection in the general population; two, the risk of SV40 transmission through blood transfusion. The research is expected to be completed in 2004 upon the completion of an ethical review.
With respect to (d), it is presumed that SV40 is being transmitted among humans, but it is not known if this transmission occurred prior to the use of polio vaccine in the late 1950s and early 1960s, or was a result of its use. No study has satisfactorily confirmed whether SV40 found in the human population is from contaminated polio vaccine, or from some other source, and epidemiological studies to date have not determine whether SV40 contaminated polio vaccine did or did not cause cancer in the recipients of vaccine.
Research shows a remarkable rise in incidence of NHL over the last 30 years, double from 1973 to 1998; the incidence rate estimated for 2002 is 14.9/20.7 (female/male) per 100,000 (age standardized). However, it is not known if the doubling of NHL in Canada is related to the presence of SV40.
On November 22, 2002, Health Canada sponsored a meeting of our partners at the National Microbiology Laboratory, NML, in Winnipeg to discuss progress on the various research projects. Health Canada informed the group that it had developed the testing methodology for detecting SV40 in cells and tissues from patients with non-Hodgkin lymphoma and was in the process of developing blood tests to detect antibody to SV40 to permit our planned seroprevalence studies. A proposal is being prepared to conduct relevant study.
With respect to (e), it is not known how many Canadians may have been exposed to contaminated vaccine in Canada, nor is it currently known if the virus is detectable in cancers in the Canadian population. The evidence to date is inadequate to accept or reject a causal relationship between SV40-contaminated polio vaccine and cancer in humans.
Health Canada and external partners including the BC Cancer Agency, the Canadian Blood and Marrow Transplant Group CBMTG, the BC Transplant Society, hospitals, provincial laboratories, as well as, academics are currently undertaking a risk assessment of SV40. This risk assessment involves a number of independent research studies which collectively aim to address several research questions, including: one, is there an any evidence of SV40 infection in the Canadian population? Two, is SV40 associated with non-Hodgkin lymphoma or other human cancers? Three, is SV40 transmissible through blood? and four, what is the risk of SV40 for the Canadian blood supply?
A proposal is being prepared to determine the relative incidence of markers indicating viral infection with lymphotropic viruses in tissues of patients with NHL and other diseases. The proposal is also aimed to corelate findings of viral infection of SV40 in tissue with clinical parameters and diagnostic subsets of NHL, and to compare prevalence of SV40 infection in tissues among NHL patients born between 1955 and 1963, before and after that period.
With respect to (f), since 1995, only approximately $20,000 for the FY 2002/03 is for testing and approximately $50,000 from the Blood Safety Surveillance and Health Care Acquired Infections Division to support the CBMTG and other groups.