Transcript Lookback study in Japan

Lookback study for transfusionrelated HBV infection in Japan
Tokyo Metropolitan Red Cross Blood Center
Masahiro Satake
Lookback study in Japan
• Aliquots from all donations have been stored
since 1997.
• When necessary, each aliquot was investigated
using individual donation-NAT (ID-NAT).
• Subjects for the study :
converters for HBs-Ag, HBc-Ab, HCV-Ab,
HIV-Ab, screening NAT for HBV, HCV or HIV
during April 1999 and February 2005
ID-NAT results in repository tubes from
seroconverted or NAT-converted donors
No. of ID-NAT
performed
No. of positive
tubes
Positivity rate
(%)
HBV
20,033
261
1.30
HCV
4,371
2
0.05
HIV
1,673
1
0.06
total
26,077
264
1.01
(‘99 April ~ ’05 February)
No. of HBV ID-NAT positive but pool-NAT
negative donors estimated by lookback study
Conversion /
year
ID-NAT positive
No. of ID-NAT
positive donors
HBV-pool
NAT
80
3.75%
3.0
HBｓ-Ag
124
3.7％
4.6
HBｃ-Ab
3269
1.0%
32.6
total
3473
1.16％
40.2
These donations do not directly relate to infectivity.
The infectivity of HBV-ID-NAT positive components
No. of ID-NAT positive donation
No. of components released
transfused・・・・・・・・・・・
discarded・・・・・・・・・・・
unknown・・・・・・・・・・・
267
321
293
16
12
Outcome of transfused patients（191 reports available ）
HBs-Ag conversion
6
HBV-DNA conversion
2
HBs-Ab conversion
3
positive, but no information before transfusion 7
markers not changed
60
dead
99
discharged etc.
14
The infectivity of HBV-ID NAT-positive components
HBV infected 11
Undetermined 7
No change
60
others
115
Infectious risk when
transfused with ID-NAT
positive blood
11／78～18 ／78
6～10 HBV infections per year
Infectivity of HBV ID-NAT positive components
Component
Infected
No
change
Window
period
10
21
31
32% (10/31)
1
39
40
2.5% (1/40)
total
infectivity
(HBcAb -)
Chronic
carrier
(HBcAb +)
Infectivity of W.P. component is 13 times as high as that from chronic carrier.
Implicated components
component
RBC
FFP
Platelet
From window From chronic
period
carrier
5 / 10
(50%)
0 / 19
3 / 10
1 / 18
(30%)
(6%)
2/4
(50%)
0/1
Established cases for HBV infection
Disorders of patients
hematologic malignancy
gastric cancer
dissecting aortic aneurysm
shock due to multiple trauma
rheumatoid arthritis
unknown
2
2
1
1
1
4
ID-NAT in repository tubes
--- voluntarily reported HBV cases --100
4
virus (+)
virus (-)
4
unknown
5
6
75
4
57
31
36
1999
2000
42
0
2001
2002
2003
The risk of HBV infection under current
screening algorism including 50p-NAT system
Sources
HBV-infection
Lookback investigation
6～10
Voluntary report of infection
５
total
１1～１5 cases／year
Lookback study for HCV and HIV
No. of ID-NAT
performed
HCV
4,371
HIV
1,673
No. of positive tubes
2
(1 donation before NAT
implementation)
1
(Established infected case)
Seroconversion possibly due to nonspecific reaction was
also subjected to lookback study.
Estimates for the Occurrence of TransfusionTransmitted Viral Diseases in Japan
• HBV
HBV+ donation detectable only by ID-NAT : 1 / 150,000
11～15 infection cases per year
（1 infection / 3.6～5.4 x 105 components）
• HCV （difficult to estimate）
HCV+ donation detectable only by ID-NAT : 1 / 24 million
（1 component / 4 years）
• HIV （difficult to estimate）
HIV+ donation detectable only by ID-NAT : 1 / 12 million
（1 component / 2 years）