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Discussion on screening of blood for rare viruses must go beyond the blood transfusion services
MJA 1997; 166: 454 Subsequently cited in Moaven L. Should we be screening blood donors for hepatitis G virus? The case for screening. MJA 1998; 169: 373-374
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©MJA1997
In the past, the acute complications of transfusion were perhaps
viewed by the community as acceptable risks. The contamination of
blood products by HIV changed all that; here was a bloodborne
infection that produced life-threatening complications years
after transfusion. Virtually all patients who received
HIV-contaminated blood or blood products became chronically
infected and progressed to AIDS and a premature death. Furthermore,
in the community, HIV was widely perceived as being associated with
society's stigmatised or marginalised groups.
Human T-cell lymphotropic virus type I (HTLV-I) was discovered
before HIV, but screening of blood for HTLV-I was not implemented with
the same degree of urgency as for HIV. In most developed countries,
HTLV-I was considered to be an exotic infection which posed a minimal
threat to the blood supply. Even in countries endemic for HTLV-I, less
than 5% of people with the infection develop serious disease.1,2 There is so little HTLV-I-related
morbidity in Australia that single cases still merit case reports.3
Nevertheless, by the mid 1980s HTLV-I screening tests were ready for
mass use, and Japan, the only industrialised country with a
substantial prevalence of HTLV-I infections, began screening blood
for the virus. With litigation arising from HIV infection with
transfusion of blood or blood products in full swing in the
industrialised world, the American Red Cross in 1988 decided to
screen all donations for HTLV-I.4
The answer to this question depends very much on the perspective being
taken. For blood transfusion services wishing to reduce the risk to
the recipients of their products, not to mention their medicolegal
vulnerability, the decision to screen all donations for HTLV-I can
seem very logical, even if the prevalence of infection is very low. In
the United Kingdom, where HTLV-I prevalence in blood donors is some
five times higher than in Australia,6 universal screening has not been
adopted, but there have been recent calls to review this policy.7 From the point of view of
governments and tax-payers, facing ever-increasing demands on
health care and escalating health budgets, perhaps health
expenditure in other areas may have had a greater impact in
value-for-money terms. Screening blood donations for HTLV-I in
Australia has an annual cost of two to three million dollars per year in
test kits alone, and laboratory staff and handling costs probably
account for seven million dollars (E Dax, Director, National
Serological Reference Centre, personal communication).
Is it possible to reconsider the decision to screen blood donations
for HTLV-I? Put in another way, can a decision be made to reduce the
safety of the blood supply, even if only to a very small degree? If the
answer is yes, the process of re-evaluation should take place in a
broader context than has been adopted in the past. A framework must be
established so that the decision is made by the community as a whole,
not just by the blood transfusion services. The recent establishment
by the Australian Health Ministers Advisory Council of a Blood and
Blood Products Committee, and the national restructuring of the
State and Territory Red Cross blood transfusion services into a
single corporate entity (see page 453 of this issue of the journal), are valuable steps
towards integrated decision-making, but these changes do not go far
enough. These two entities need to be brought closer together and
utilise expertise in public health, health economics and other
areas, as required.
A review of HTLV-I screening would ideally be carried out in the
context of other infectious agents that can be transmitted by blood.
It may be more cost-effective to screen for agents such as parvovirus
B19 (which causes pure red cell aplasia), although susceptibility is
limited to a very small proportion of the population. Hepatitis G
virus and human herpesvirus type 8 (associated with Kaposi's sarcoma
and B-cell body cavity lymphoma) are newly discovered viruses that
may also require consideration for routine screening once tests
become available.8
If deliberations about blood screening are to take place in a broader
context, thought must also be given to legal changes that shift the
burden of sole liability from the blood transfusion services. The New
Zealand "no-fault" compensation model has long been discussed as one
possible solution. Another approach may be legislated protection of
the blood transfusion services against litigation, provided
bloodscreening policies were determined and implemented according
to specified guidelines.
Although HTLV-I-related disease has been rare in Australia, HTLV-I
infection is present at relatively high levels in some populations of
indigenous people, and probably also in some migrant groups. If it is
decided to reconsider HTLV-I screening of donations, its
abandonment is not the only alternative to the status quo. A policy of
screening only new donors would have detected all 21 HTLV-I-positive
individuals in the time period of Whyte's study and reduced the extent
of testing required by over 80%. Therefore, it may be sufficient to
screen blood donors only once and thereafter assume that their HTLV-I
status remains unchanged, or carry out testing again after five or 10
years. Another approach could be to use the donor interview to
identify people who may be at higher risk of HTLV-I. Screening on the
basis of country of birth, for example, would have detected a third of
the individuals confirmed positive for HTLV-I in Whyte's study.
Blood transfusion will never be risk-free. With the risk-benefit
balance now many times more favourable than it has ever been, perhaps
the time is right to engage the community in a discussion that brings
both public health and economic issues into decision-making about
blood safety.
John M Kaldor
<URL: http://www.mja.com.au/>
© 1997 Medical Journal of Australia.
©MJA 1997
Despite the steady reduction over time in the risks associated with
blood transfusion, there has been a parallel increase in the
community's expectations of the safety standards that must be met by
blood and blood products.
Can a decision
be made to reduce the
safety of the blood supply, even if only to a very small degree?
In Australia, a response was required. The national peak blood
transfusion advisory body, the Red Cross National Blood Transfusion
Committee, recommended universal screening of blood donors in 1989
and again in 1991, but the National Health and Medical Research
Council did not concur because, it was argued, the costs of universal
screening far outweighed any public health benefit.5 Despite these differences in
professional judgements, by early 1993 all Australian Red Cross
blood banks had introduced HTLV-I screening. In this issue of the
Journal, Whyte outlines for the first time in
Australia the results of this screening and shows that Australian
blood donors have among the lowest HTLV-I prevalence rates ever
recorded. He then goes on to implicitly ask whether it is time to review
the screening policy.
The contrasting recommendations of the Australian Red Cross and the
National Health and Medical Research Council on HTLV-I screening
highlight a deficiency in the decision-making processes on aspects
of blood transfusion in Australia. While governments fund State and
Territory blood transfusion services and strongly influence their
functioning, the Australian Red Cross is the legal entity liable for
the blood products. The decisions by the blood transfusion services
may inevitably be based on a narrower view of the issues involved than
that shared by the community.
Deputy Director and Professor of Epidemiology
National Centre in HIV Epidemiology and Clinical Research,
University of New South Wales, Sydney, NSW.