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Cancer linked to vaccine fouled by monkey virus
Polio inoculation
Polio inoculation
Shelley Page
Ottawa Citizen
Ottawa Citizen
OTTAWA - An increasing number of medical researchers believe a monkey virus that
contaminated polio vaccine in the 1950s and early 1960s is causing cancer among the millions
of Canadians who got the vaccine.
contaminated polio vaccine in the 1950s and early 1960s is causing cancer among the millions
of Canadians who got the vaccine.
Researchers at first thought Simian Virus 40 (SV40) was linked only to rare brain, bone and
lung cancers.
lung cancers.
But last month, two studies in the British journal The Lancet found traces of the virus in the
tumours of almost half of patients with non-Hodgkin's lymphoma, a relatively common cancer
in Canada, with 6,200 new cases diagnosed last year. The number of cases of non-Hodgkin's
lymphoma has inexplicably doubled over the past 30 years.
tumours of almost half of patients with non-Hodgkin's lymphoma, a relatively common cancer
in Canada, with 6,200 new cases diagnosed last year. The number of cases of non-Hodgkin's
lymphoma has inexplicably doubled over the past 30 years.
Health Canada has now said it will lead a number of studies -- slated for final approval later
this month -- that will attempt to prove or disprove SV40's link to cancer.
this month -- that will attempt to prove or disprove SV40's link to cancer.
"The issue is, does it really cause cancer in humans?" said Dr. Antonio Giulivi, the
department's director of Health Care Acquired Infections. "There is still considerable debate."
department's director of Health Care Acquired Infections. "There is still considerable debate."
Health Canada and the Canadian Bone Marrow Transplant Group will test samples developed
from about 20 non-Hodgkin's lymphoma patients at Princess Margaret Hospital in Toronto.
"We want to see if we can find SV40," said Dr. Giulivi.
from about 20 non-Hodgkin's lymphoma patients at Princess Margaret Hospital in Toronto.
"We want to see if we can find SV40," said Dr. Giulivi.
Canadian researchers will then study the tumours of 50 non-Hodgkin's lymphoma patients
being treated at the Ottawa Hospital or in Toronto to see if they have the virus in their
tumours. They will also study whether chemotherapy and other treatments alter the virus, or
its presence in tumours.
being treated at the Ottawa Hospital or in Toronto to see if they have the virus in their
tumours. They will also study whether chemotherapy and other treatments alter the virus, or
its presence in tumours.
The team will also follow other patients with other forms of cancer to see if they have traces
of SV40.
of SV40.
Patients who have never been vaccinated have also been found to have SV40 in their
tumours, adding to the mystery of how the virus is transmitted. Dr. Giulivi said they will
conduct tests to see if patients were infected with SV40 during bone marrow transplants.
tumours, adding to the mystery of how the virus is transmitted. Dr. Giulivi said they will
conduct tests to see if patients were infected with SV40 during bone marrow transplants.
Dr. David Malkin, a Canadian researcher, wrote a controversial editorial in last month's Lancet
saying there is enough evidence to show SV40 plays a role in the development of human
cancers.
saying there is enough evidence to show SV40 plays a role in the development of human
cancers.
"I was one of the non-believers. Now I'm a believer. There is no rational way I can figure out
any other explanation for my results," Dr. Malkin, an oncologist at the Hospital for Sick
Children, said in an interview.
any other explanation for my results," Dr. Malkin, an oncologist at the Hospital for Sick
Children, said in an interview.
He has found SV40 in the tumours taken from families who suffer from Li-Fraumeni syndrome,
which causes clusters of cancers.
which causes clusters of cancers.
He says proteins from SV40 turn off tumour-suppressor genes in humans, according to Dr.
Malkin. "The antigen for the virus inactivates these genes, it makes them non-functional. It's
doing something that is biologically very important."
Malkin. "The antigen for the virus inactivates these genes, it makes them non-functional. It's
doing something that is biologically very important."
Canadian children began falling ill with polio in the early 1950s. The Salk and Sabin vaccines
not only brought relief to terrified parents, but effectively ended the epidemic. Between 1955
and 1961, an estimated nine million Canadians, about half the adult population and most of
the children, were vaccinated, primarily with the Salk vaccine.
not only brought relief to terrified parents, but effectively ended the epidemic. Between 1955
and 1961, an estimated nine million Canadians, about half the adult population and most of
the children, were vaccinated, primarily with the Salk vaccine.
Most of the vaccine came from Connaught Laboratories in Toronto.
However, inside the early versions of both vaccines lurked a monkey virus. The virus came
from dead monkeys whose kidney cells were used to culture the first vaccines. Production was
halted after the virus was found.
from dead monkeys whose kidney cells were used to culture the first vaccines. Production was
halted after the virus was found.
While it is believed that SV40 poses little risk to the vast majority of those who received the
vaccines, it may still be present in the bodies of millions of Canadians.
vaccines, it may still be present in the bodies of millions of Canadians.
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