UK blood donors identified as at increased risk of vCJD are
to be notified of their status
Emerging Infections and Zoonoses Department, Health Protection
Agency Centre for Infections, London, United Kingdom
England’s Department of Health have announced the beginning
of notification of a group of individuals who are newly identified as at increased
risk of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom (UK)
[1,2]. These are people who have donated blood that was transfused to patients
who subsequently developed vCJD. This currently concerns around 100 donors
to three vCJD cases.
vCJD infection has been observed in two recipients of blood transfusions
from donors who later developed vCJD [3,4]. One of these recipients did
not develop vCJD and died of causes unrelated to the disease. Although other
exposures, including, most notably, dietary exposure to BSE, cannot be excluded
as the source of these patients’ infections, it is considered highly probable
that these two patients were infected by blood transfusion. These reports
added to previous evidence of vCJD infectivity in blood obtained from experiments
in animals, and led to the conclusion that transfusion should be considered
a possible route of vCJD transmission in humans.
Over 2 million blood donations are collected each year in the UK by the
blood services, and over half a million patients receive transfusions annually.
Of the 150 people who have died from vCJD in the UK to 1 July 2005 ,
only four have been confirmed as having received blood transfusions that
may be associated with their subsequent development of vCJD. (For two other
cases, symptoms developed before or very shortly after transfusion and therefore
transfusion is not considered a possible source of their infections.) For
one of these cases, the probable source of infection has already been identified,
as one of the donors went on to develop vCJD. For the remaining three cases,
transfusion remains a possible source of the recipient’s infection.
A risk assessment by the Department of Health looked at the probability
of donors to vCJD cases being the source of a recipient’s infection, and
therefore the probability that the donors themselves are infected . The
United Kingdom CJD Incidents Panel  considered this risk assessment and
recommended that such donors should be considered as ‘potentially at-risk
of vCJD for public health purposes’ unless the probability of being infected
with vCJD (as implied by donation to a vCJD case, and estimated with precautionary,
or ‘worst case’, assumptions) falls clearly below 1%.
Unless there is evidence to the contrary, the assumptions for this calculation
are: that an infected donation would certainly infect the recipient (the
‘worst case’ assumption); that there is no way of distinguishing between
the contributing donors (and recipient) in terms of risk of primary vCJD
infection (e.g., that all had been resident in the UK during the BSE outbreak),
and that there is no other significant alternative infection route for the
recipient, such as having been operated on with instruments previously used
for healthcare interventions on a patient with vCJD.
These individuals are being informed that they are 'potentially at-risk
of vCJD for public health purposes' so that special public health precautions
can be taken to reduce the risk of person-to-person transmission of vCJD
during their healthcare. Specifically these are: not to donate blood, organs
or other tissues, and to inform their healthcare providers of their 'at-risk'
status in order that infection control guidance  can be implemented for
the instruments used in certain invasive healthcare procedures (and so that
certain invasive healthcare procedures that have already been carried out
on them can be considered by the CJD Incidents Panel).
The 100 or so individuals involved are being informed by the UK Blood Services.
Their general medical practitioners are being briefed by the Health Protection
Agency and Health Protection Scotland so that they can provide further information
and support to their patients, and assist with implementation of the recommended
public health precautions, as required. Where past invasive healthcare procedures
have been conducted on these individuals, and potentially contaminated instruments
may be a risk for other patients, local health protection staff are asked
to consult the CJD Incidents Panel for advice about whether any actions
should be taken.
Since its establishment in 2000, the CJD Incidents Panel has issued advice
relating to several groups of patients identified as at increased risk of
CJD. Other groups of patients who are considered to be ‘potentially at-risk
of vCJD for public health purposes’ include: certain patients who have been
operated on with instruments previously used for healthcare interventions
on a patient with vCJD; recipients of blood from donors who later developed
vCJD, and patients who have been treated with plasma products that may have
been contaminated with vCJD infection. This new notification of ‘donors
to vCJD cases’ is a further precautionary measure to reduce the possible
risk of secondary transmission of vCJD in the UK. Further information about
this notification can be found at http://www.hpa.org.uk/infections/topics_az/CJD/vCJDBloodDonors.htm.
This article has been adapted by the author from reference 1