Samreen Ijaz

1

Indigenous HEV infection in the UK a hazard for
blood donation?

• Samreen Ijaz
• Virus Reference Department
• Health Protection Agency

2
HEV Infections in England and Wales (2005 study)
HEV seropositive samples with no travel history
identified from 1996-2003 at CPHL
3
HEV seroprevalence in England(year 1991)
4
HEV prevalence by age-group1991 vs 2004
Temporal shift
5
Seroprevalence rates vs clinical disease

• 13 seroprevalence high compared to the low rate
  of clinically evident disease
• Incidence estimates between 1991 and 2004
  indicate that 62 000 cases of HEV occurred per
  year
• Mathematical modelling suggests that incidence
  does not vary with age group
• Shared risk factors common to all age groups

6
Indigenous HEV in England and Wales

• Routes of transmission in the non-travellers
  could not be ascertained from this study
• Specific risk factors for acquiring indigenous
  HEV infections currently remains undefined
• The detection of HEV Abs and RNA in swine and
  subsequently in several other animals has led to
  suggestions of a potential zoonosis with animals
  acting as reservoirs for HEV infection in humans
• 85 of UK pigs are anti-HEV pos.
• Recommended that indigenous HEV be considered a
  level 2 zoonosis (potential zoonosis), thus
  requiring enhanced surveillance in the UK

7
Parenteral transmission of HEV?

• Higher HEV Ab levels reported in
• paid blood donors positive for other blood borne
  viruses
• repeatedly transfused haemodialysis patients
• Subsequent reports of transfusion transmitted
  HEV from France, Japan and Saudi Arabia
• Studies from Japan have demonstrated that a
  small but significant proportion of their blood
  donors were viraemic and potentially able to
  cause transfusion-associated HEV
• in the absence of elevated ALT and signs or
  symptoms of hepatitis
• When characterised, the strains involved in the
  cases from Japan were shown to be indigenous
  viruses

8
Post transfusion hepatitis in the UK

• UK blood donor
• 14 days after his donation he became ill with a
  flu-like illness
• 10 days later he became jaundiced
• Blood donor reported illness to the blood service
  but components of his donation had already been
  used
• Testing for viral markers
• HAV, HBV, HCV, CMV and EBV negative
• HEV IgM and IgG positive
• HEV RNA positive genotype 3

9
Post transfusion hepatitis in the UK
Blood Donation
platelets
red cells
Pool from 4 donors which is resuspended using
plasma from one of the donors (not the HEV pos
donor)
Would contain 20-30mls of the donors plasma
Patient 2
Patient 1
INFECTED
UNINFECTED

• HEV infection in the recipient related to dose?

10
Post-transfusion hepatitis

• Post transfusion hepatitis in the UK is now a
  relatively rare event with enhanced surveillance
  through the Serious Hazards of Transfusion (SHOT)
  reporting system
• Approximately 62 000 cases occur each year
• Suggests that there are a significant number of
  subclinical HEV infection
• Current screening policy in the UK does not
  include HEV testing
• Should we worry?

11
Initial studies to look at UK blood donors

• HEV IgG testing on
• 262 samples from ordinary blood donors
• 339 samples from donors with a history of
  jaundice (all anti-HBc negative)

25
20
15

10
5
0
17 - 29
30 - 39
40 - 49
50 - 59
gt 60
Age (yrs)
12
HEV seroprevalence in UK blood donors

• HEV seroprevalence trend similar in blood donors
  to general population
• Similar seroprevalence rates between ordinary and
  jaundice history donors
• HEV unlikely to be responsible for donors
  reporting history of jaundice
• History of jaundice not accurate screening method
  for excluding at risk donors
• Further HEV IgM RNA testing carried out on all
  donors
• 4 HEV IgM pos
• 0 HEV RNA pos
• EVIDENCE OF RECENT HEV INFECTION IN DONOR
  POPULATION

13
Further work

• Evidence of seroconversion in the blood donor
  panel
• Evidence of HEV RNA in minipools
• Concern of post transfusion hepatitis in
  transplant recipients and the immunosuppressed

14
Acknowledgements

• Richard Tedder
• Mathew Beale
• Kate Tettmar
• Roger Eglin
• NHS Blood and Transplant