In December 1997
Channel 4 showed a Dispatches investigative television documentary I
co-produced with Rosie Thomas. It was on one of the most serious
topics I have ever investigated. What we found was more serious than
the Mad Cow outbreak - but perhaps because our program went out just
before Christmas, the newspapers did not cover it. The following is a
copy of the leaflet I wrote to go with the program. Please
distribute. Jani Roberts.
Channel 4 Television
Contaminated polio vaccines
In 1997, an international scientific workshop held in
Washington DC heard report after report that a monkey virus &endash;
simian virus 40 (SV40) &endash; had been found in many human cancers
of the brain, bone and lining of the lungs. This virus had reached
the human population between 1955 and 1963 through the contamination
of millions of doses of polio vaccine. Recent research has shown that
even people who have never been exposed to this polio vaccine are at
This leaflet explains how all this came about and what it
means for human health. It concludes with a list of organisations
that can be contacted for further help and information.
In 1961&endash;2, the Medical Research Council in Britain
reported that a monkey virus &endash; simian virus 40 (SV40) &endash;
that caused cancer in hamsters was contaminating the polio vaccine
given to millions of people around the world. However, SV40 was then
presumed not to harm humans. When, in 1972, the New England Journal
of Medicine reported that the virus had been detected in human brain
cancers, no alarm was taken. Then in 1996, a number of scientists
reported finding SV40 in many human cancers of the bone, brain and
lung lining, and that the virus causes 'severe chromosome damage' in
These research findings were finally taken very seriously.
In January 1997, the first international scientific workshop on SV40,
sponsored jointly by the US government's major health agencies, was
held in Washington DC. Over 100 scientists from around the world
attended &endash; as did a senior representative of the UK's
Department of Health and film producers commissioned by Channel 4's
Many at this conference now believe that the most likely
source for the monkey virus contamination of the human population was
the millions of doses of polio vaccine distributed around the world
between 1955 and 1963, including in the UK. That the polio vaccine
had been contaminated was actually admitted in Parliament back in
1988, but at that time the government said it believed the virus to
be harmless in humans. But research from many laboratorities was
presented at However, in the opinion of the 1997 conference, that
indicated that SV40, &endash; now endemic in the human population,
could &endash; could have a role in causing thousands of human
It is hoped that this leaflet will answer any questions
you may have.
What is a vaccine and how does it work?
All vaccines work by stimulating the body's natural immune
system to produce antibodies that will protect us from specific
illnesses. The stimulus used is a weakened or killed version of the
virus or bacterium responsible for the targeted disease.
Most of the common vaccines given during childhood
&endash; such as those for polio, measles, mumps and rubella (German
measles) &endash; use a living virus but only after it has been
'attenuated', or weakened, by various methods such as heating or
being transplanted many times from cell to cell. With attenuated
vaccines, care has to be taken to ensure that the virus (or
bacterium) is sufficiently weakened so as not to cause the severe
form of the disease, while at the same time being strong enough to
confer immunity. Great care also has to be taken to ensure that the
vaccines are not contaminated in any way.
How did the polio vaccine come to contain monkey
When the polio vaccine invented by Dr Jonas Salk first
became available on a large scale in 1955, there was a rush to use it
to help eliminate what could be a terrible disease in children and
young people. As the virus needed for the vaccine grew well in the
kidney tissues of monkeys, there was a great demand for these
kidneys. They were taken from many thousands of Indian Rhesus monkeys
imported into the US and Europe.
It was very quickly discovered that Rhesus monkey viruses
were getting into the polio vaccine. However, health authorities
initially did not think that this was dangerous because the Salk
polio vaccine most commonly used in the 1950s and early 1960s was
based on killed polio viruses. It was presumed that the method used
to kill the polio viruses would also kill all the monkey viruses
contaminating the vaccine.
This presumption continued throughout the 1950s despite
the discovery in 1956 by US government scientist Dr Bernice Eddy that
some agent in the monkey kidneys appeared to be causing cancers in
hamsters into which it had been injected. By 1958, this agent had
been identified as SV40 (that is, the 40th simian virus identified).
It was also reported that this virus was not found in samples from
humans unexposed to the polio vaccine but was found in 7 of every 13
people inoculated against polio. SV40 soon also became very well
known in laboratories for its ability to 'jump species' &endash; that
is, its ability to live in species other than monkeys.
The research that forced US and UK authorities to act was
published in March 1961 in the British medical journal, the Lancet.
This showed that SV40 survived the process that killed the polio
vaccine and was alive and active in the vaccine. Of 20 British
children who had received the Salk polio vaccine, 13 tested positive
for SV40, but none of the children who had not had the Salk vaccine
tested positive. By this stage, many millions of doses of
contaminated polio vaccine had been administered worldwide to
children, young adults and expectant mothers.
Confirmatory research by the UK Medical Research Council
was published in the Lancet in June 1961: 12 children who had
received three doses of the Salk polio vaccine were tested &endash;
and 11 of them were positive for SV40.
When was the link between cancer and SV40
At about the same time that the survival of active SV40 in
polio vaccine was confirmed, reports were also surfacing that SV40
caused cancers. In March 1961, Dr Eddy sent a paper to the medical
journal Virology in which she demonstrated that injection of newborn
hamsters with Rhesus monkey kidney cell cultures caused cancers in
109 out of 154 cases (Virology did not publish this until 1962). Soon
came news that SV40 might be responsible for cancer in humans as well
as in laboratory animals. The 1961&endash;62 Annual Report of the
Medical Research Council stated: 'There have been recent reports that
it [SV40] causes a change in behaviour of human cells grown in tissue
culture: a change which may or may not be neoplastic [cancerous] in
character. Further intensive studies of the virus are obviously
In 1962, American research papers were published showing
that human tissue became cancerous when exposed to SV40. Then in 1972
in the US, a virus related to SV40 was isolated for the first time
from human brain cancers. No follow-up research was done in the UK.
Has the UK government confirmed that the British polio
vaccine was contaminated with SV40?
Yes. On 19 July 1988, the Minister for Health was asked in
Parliament 'whether polio vaccine used in the UK in the late 1950s
and the early 1960s was contaminated with SV40 and what effects this
known enhancer of genetic change in other micro-organisms is
considered to have in its recipients?' He answered: 'I am advised
that some of the polio vaccine used in the UK at that time contained
SV40. However, I am also advised that there is no evidence of adverse
effects on recipients.'
The Minister added to this in an answer to a follow-up
question: 'There has been no separate continued observation of those
people in the UK who might have received vaccine contaminated with
SV40.' This has been the situation up to the present.
Who manufactured the contaminated polio vaccine used in
the UK in the 1950s?
The American companies Parke Davis, Pitman-Moore and
Connaught Laboratory all supplied the UK in the 1950s with at least
20 million doses of polio vaccine of which over 6 million doses may
have been contaminated with SV40. The vaccine was manufactured in the
UK by both Glaxo and Burrough Wellcome and their supplies may have
been similarly contaminated. In 1959, Pfizer also started
manufacturing polio vaccine for recipients in the UK.
Does polio vaccine still contain SV40?
It does not &endash; and has not, to the best of our
knowledge, since 1963.
Steps were taken in 1961 to eliminate the SV40
contamination from all freshly manufactured polio vaccines. These
measures included ending the use of Indian Rhesus monkeys and instead
using African green monkeys. The latter are free of SV40
contamination in the wild, but since they rapidly become infected in
laboratory conditions, they need to be constantly monitored after
In addition, from 1962 the injected Salk vaccine was
replaced by the orally administered Sabin type, which contains a
living 'attenuated' polio virus. This vaccine cannot infect people
with SV40 simply because it is taken by mouth: the human gut filters
out all SV40 viruses, thus preventing them from infecting us.
However, even after SV40-free vaccine became available,
the US authorities did not simultaneously withdraw batches of
contaminated polio vaccine that had already been released. Since it
had a two-year shelf life, some contaminated vaccine was available as
late as 1963.
Was SV40 the only monkey virus to contaminate the polio
Several other monkey viruses have been found in polio
vaccine, most notably simian immunodeficiency virus (SIV), which has
only been screened out since 1987. This virus is endemic among
African green monkeys, the species currently used in the manufacture
of UK and US polio vaccine. A herpes-like monkey virus is also
filtered out. Another possible contaminant is SCMV (simian
cytomegalovirus), isolated in 1994 from human brain tissues taken
from patients who had suffered from previously unexplained
encephalitis and chronic fatigue syndrome. This virus is also likely
to come from African green monkeys, the species used nowadays in the
manufacture of polio vaccine. Very little research has been done on
any of these viruses.
We have focused on SV40 as it is the most understood of
the monkey viruses. Because it is used in medical experiments
requiring a virus that can jump species, its DNA has been fully
analysed and so it is easily identified. It is also the monkey virus
that has attracted most research into its links with human diseases.
A number of other monkey viruses &endash; such as SV29, SV39, SV28
and SV38 &endash; are known to reproduce in human tissues.
Can polio vaccine be made without using monkeys?
Yes, without a doubt. At least one major drug company
sells two forms of polio vaccine: one grown in cloned human tissue
(an established vaccine manufacturing method, also used to produce
rubella vaccine), the other in monkey kidney tissue. The human
tissue-grown polio vaccine comes with no risk of cross-species virus
contamination. However, the wild monkey tissue-grown version is
reportedly slightly cheaper to make.
The World Health Organisation recommends three
manufacturing processes for polio vaccine:
1 Wild monkey kidneys. The company SmithKline Beecham
manufactures most of the polio vaccine for the UK by this method.
2 Cloned human tissue. This method is utilised in some
European countries and in Canada. The US Connaught Laboratory makes
polio vaccine both by this method and from wild monkeys, selling
human tissue-based vaccine in Canada and monkey tissue-based vaccine
in the US.
3 Cloned monkey tissue. This method is safer than using
tissue from wild monkeys. Suitable cloned tissue stocks are
maintained by WHO for use in manufacturing polio vaccine.
While permitting all three methods, the World Health
Organisation points out that the first carries the greatest risk of
viral contamination. Therefore it recommends that, if this method is
used, rigorous screening and animal testing should also be adopted.
What does SV40 do in humans?
In 1996, a scientist in Texas reported that SV40 causes
'severe chromosome damage in virtually every human fibroblast [cell
producing collagen fibres in connective tissue] in which it is
expressed.' Recent experiments carried out in laboratories around the
world and reported at the 1997 SV40 conference in Washington also
indicate that it causes severe damage to human chromosomes. In
particular, it appears to turn off the p53 gene that controls the
multiplication of cells and thus eliminates part of our protection
SV40 has now been found concentrated in certain human
cancers. For example:
in 33&endash;50% of bone cancers
in 60&endash;80% of certain brain cancers
in 60% of mesotheliomas &endash; a cancer of the lung
lining, which claims some 1,200 victims a year in the UK alone.
It is possible that we will find that SV40 plays an even
larger role, perhaps by helping to cause cancers without becoming
concentrated in them. For example, SV40 has not been found in human
breast cancers, but a 1996 report of German research using laboratory
animals stated that SV40 'induces breast cancer with a high
efficiency' in 100% of breastfeeding and 70% of virgin animals, while
not making all the cells transformed positive for SV40.
Can SV40 work with asbestos and other environmental
factors to cause cancers?
This is still being investigated. Mesolthelioma &endash;
cancer of the lining of the lungs &endash; has long been associated
with exposure to blue asbestos, and it is now found to be associated
with SV40 in about 60% of cases. It could be that SV40 facilitates
the production of this cancer by switching off the p53 gene and thus
leaving the body more vulnerable to factors such as asbestos that are
known to cause cancer. This has important legal ramifications for
companies currently being fined millions of dollars by the courts for
exposing workers to the dangers of asbestos. They could now argue
that the legal responsibility must be shared by those responsible for
the SV40 presence in the polio vaccine.
The only published British research on SV40 was presented
by Alan Gibbs at the 1997 SV40 workshop in Washington. He stated that
an examination of nine mesothelioma tumours held at his Welsh
hospital showed four to be contaminated with SV40.
If SV40 has now been screened out of the vaccine,
surely we are now safe from it?
Unfortunately this does not seem to be the case. The virus
now seems to have become endemic among the human population. For
instance, it has been found in brain tumours in children not exposed
to the contaminated vaccine, and the best theory for why this has
happened is that it was passed from mothers to children. In addition,
at the SV40 workshop in Washington, Professor Mauro Tognon of Verona,
Italy, reported having found SV40 in 8 out of 20 samples of 'healthy'
What can be done to counter the damage done by
Hope was held out by a leading into this virus, Michele
Carbone, at the SV40 workshop. Now that we know how SV40 affects the
human chromosome, he said, we may be able to devise ways of turning
the p53 gene back on, perhaps by vaccination. But research on this is
at a very early stage.
The Informed Parent
PO Box 870
Middlesex HA3 7UW
Tel: (0181) 861 1022
Contact: Faith Easy
This organisation has researched the medical literature
about SV40 in order to 'promote awareness of vaccination issues to
preserve the freedom of an informed choice'.
1 Gawsworth Road
Cheshire WA3 3RF
Tel: (01942) 713 565
Fax: (01942) 201 323
Contact: Jackie Fletcher
A support group for individuals who have been vaccine
National Vaccine Information Center
Suite 206, 512 W Maple Avenue
Contact: Barbara Loe Fisher
An American organisation that raises funds for research
into SV40 and sells an information pack on this issue.
Asbestos-Related Disease Association
80 Raymeer Drive
Nottingham NG5 5FS
Tel: (0115) 927 5108
: (0115) 903 7791 (24-hour helpline)
Self-help group for all with an asbestos-related health
problem, formed to help the victims and their families in every way
BACUP: British Association of Cancer United Patients,
Their Families and Friends
3 Bath Place
London EC2A 3JR
Tel: (0171) 696 9003
For general enquiries about cancer, not for information on
If you want to investigate the medical literature on the
subject of SV40, the following are the main papers, in chronological
Eddy, B, Morris et al., Virology 3, 1957, p. 380 (accepted
for publication 3 December 1956).
Sweet, B H and Hilleman, M R, 'The vacuolating virus
SV40', Proceedings of the Society of Experimental Biological Medicine
105, 1960, pp. 420&endash;7. This reports that, from 1958, SV40
viruses had been 'repeatedly encountered'.
Goffe, Alan, Hale, James and Gardner, P S, Letter, Lancet,
18 March 1961.
Eddy, B, Morris, Borman, G S, Grubbs, G E et al.,
'Identification of the oncogenic substance in Rhesus monkey kidney
cultures as SV40', Virology 17, 1962, pp. 65&endash;75.
Shein, H M and Enders, J F (of the Harvard Medical
School), 'Transformation induced by Simian Virus 40 in human renal
cell cultures', Proceedings of the National Academy of Science (US)
48, 1962, pp. 495&endash;500.
Weiner, L, Herndon, R and Narayan, O, 'Isolation of virus
related to SV40 from patients with progressive multifocal
leukoencephalopathy', New England Journal of Medicine 286, 1972, pp.
Martin, W J, Ahmed, K N, Zeng, L C, Olsen, J-C, Seward, J
G and Seehrai, J S, 'African green monkey origin of the atypical
cytopathic "stealth virus" isolated from a patient with chronic
fatigue syndrome', Clinical Diagnosis of Virology 4, 1995, pp.
Lednicky, J A et al., 'Natural simian virus strains are
present in human choroid plexus and ependymomo tumors', Virology 212,
1995, pp. 710&endash;17.
Carbone, M et al., 'SV40 large T antigen and p53 in human
pleural mesothelioma', Journal of Cellular Biochemistry 19A
(supplement), p. 321.
Ray, F Andrew, 'Simian Virus 40 large T antigen induces
chromosome damage that precedes and coincides with complete
neoplastic transformation', Oncogene, 1996, pp. 15&endash;24.
Carbone, M et al., 'SV40-like sequences in human bone
tumors', Oncogene 13, 1996, pp. 521&endash;35.
Pepper, Jasani, Navabi, Wynford-Thomas and Gibbs, 'Simian
virus 40 large T antigen primar specific DNA amplification in human
pleural mesothelioma tissue', Thorax, November 1996.
Published in 1997 by
Channel 4 Television
124 Horseferry Road
London SW1P 2TX
Produced by Broadcasting Support Services to accompany
Dispatches: Contaminated Polio Vaccine (an Investigative Media
Productions/Hindi Picture film for Channel 4), first shown on Channel
4 in December 1997
Writer: Janine Roberts
Editor: Paula Snyder
Editorial consultant: Nancy Duin
Distributed by Broadcasting Support Services
Broadcasting Support Services provides follow-up services
for viewers and listeners and runs long-term helplines.
To find out more about off-screen services for Channel 4
telephone (0990) 44 66 99 for a free catalogue of booklets
go to 4-Tel page 340
visit the Channel 4 website at www.channel4.com
For further copies of this publication, please send a
cheque or postal order (made payable to Channel 4 Television) for
£1.00 (including postage & packing) to:
DISPATCHES: POLIO VACCINE
PO Box 4000
London W12 8UF or Cardiff CF5 2XT
Alternatively, you can telephone (0990) 44 66 99.
If you would like to find out about health courses or
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