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15 May 2003
Fewer future deaths from vCJD predicted
than previously estimated
Dr James Irvine
Teviot Scientific Consultancy, Edinburgh
(Filed 15 May 2003)
www.land-care.org.uk
The predicted number of future deaths from vCJD
has been revised downwards. In a paper from Imperial College (London)
(1, download
PDF) Ghani et al, using epidemiological modelling, indicates
a best estimate of 100 future deaths (95% prediction interval 10-2,600).
Using vCJD data alone (i.e. excluding data from appendix tissue)
the current best estimate is now down to 40 future deaths (range
9 - 540).
The current prediction rate is substantially
less some than some of the alarming predictions made previously
(2, 3, 4, 5).
The uncertainty of the future course of the primary epidemic in
the susceptible genotype has also been substantially decreased.
Figure 1 from Ghani et al (1)
which charts the number of vCJD deaths from 1985 to 2002 has been
reproduced below. The reduced number of deaths over the past two
years is noted.
© 2003 Ghani et al, licensee BioMed Central
Ltd. BioMed Central Ltd. This is an Open Access article: verbatim
copying and redistribution of this article are permitted in all
media for any purpose, provided this notice is preserved along with
the article's original URL.
In view of this new information (which was published
on-line with commendable speed), it has to be asked whether some
of the severe controls that have been imposed (on livestock farmers
for example) should be reassessed. The new EC Directive about banning
on-farm burial of fallen livestock, for example.
This has been argued elsewhere on Land-Care (6)
in relation to the comments by the Food Standards Agency (FSA) over
relaxing the Over Thirty Months Scheme (OTMS, 7),
or indeed abandoning it as being no longer necessary in view of
the now low incidence of BSE in UK cattle.
The fall in the predicted new deaths from vCJD
also gives further indirect reassurance that BSE has not got into
sheep.
It would seem that it may now be time to reassess
the risks of transmitting spongiform encephalopathies from beast
to man. The precautionary principal is fine, but the time has to
come as the risk recedes when it should be relaxed.
www.land-care.org.uk
References
1. Ghani, Azra C., Donnelly, Christl
A., Ferguson, Neil M., Anderson, Roy M. (2003). Updated projections
of future vCJD deaths in the UK. BMC Infectious Diseases 2003, 3:4.
(Published online ahead of print:
http://www.biomedcentral.com/1471-2334/3/4).
2. Cousens, S.N., Vynnycky, E.,
Zeidler, M., Will, R.G. and Smith, P.G. (1997). Predicting the CJD
Epidemic in Humans, Nature, 385: 197-8.
3. Irvine, James (2003). Current
Assessment of the Future Prevalence of vCJD in the UK.
(Filed 12 March 2003, www.land-care.org.uk,
click
here to view).
4. Editorial Comment (2002). Predicted
Future Incidence of vCJD in the UK Population.
(Filed 2002, www.land-care.org.uk,
click
here to view).
5. Venters, G. A. (2001). New
variant Creutzfeldt-Jakob disease: the epidemic that never was.
BMJ, 323: 858-86 (View
article).
6. Irvine, James (2003). Disposal
of fallen stock.
(Filed 1 May 2003, www.land-care.org.uk,
click
here to view).
7. Irvine, James (2003). The Food
Standards Agency reviews the OTMS rule - are they going to scrap
it?
(Filed 12 March 2003, www.land-care.org.uk,
click here to view).
Further Reading Recommended by Land-Care
Irvine, James (2003). Why is it necessary to ban the burial of all
fallen stock? Part I: Is it do with the supply of drinking water?
(Filed 3 April 2003, www.land-care.org.uk,
click
here to view).
Irvine, James (2003). Why is it necessary to ban the burial of all
fallen stock? Part 2: The view of the EC Scientific Steering Committee.
(Filed 10 April 2003, www.land-care.org.uk,
click
here to view).
Irvine, James (2003). Food Standards Agency Review of OTMS: a follow
up.
(Filed 20 March 2003, www.land-care.org.uk,
click here to view).
Leake, Jonathan (2002). Test everyone for CJD, says Nobel winner.
Sunday Times, 1 Decmeber 2002.
(Filed 9 December 2002, www.land-care.org.uk,
click here
to view).
Ramasamy, I., Law, M., Collins, S. and Brooke, F. (2003).
Organ distribution of prion proteins in variant Creutzfeldt-Jakob
disease.
Lancet Infectious Diseases, 3: 214-222.
(Reproduced, with permission, on Land-Care
11 April 2003, click
here to view).
Land-Care Editorial (2002). As many potential new cases of CJD from
one medical slip-up than allegedly through BSE related sources in
a whole year.
(Filed 30 October 2002, www.land-care.org.uk,
click
here to view).
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