1. Lookback study for transfusion- related HBV infection in Japan Tokyo Metropolitan Red Cross Blood Center Masahiro Satake

2. 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 Lookback study in Japan

3. ID-NAT results in repository tubes from seroconverted or NAT-converted donors No. of ID-NAT performed No. of positive tubes Positivity rate (%) HBV20,0332611.30 HCV4,37120.05 HIV1,67310.06 total 26,0772641.01 (‘99 April ~ ’05 February)

4. 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 803.75%3.0 HB ｓ -Ag 124 3.7 ％ 4.6 HB ｃ -Ab 32691.0%32.6 total3473 1.16 ％ 40.2 These donations do not directly relate to infectivity.

5. The infectivity of HBV-ID-NAT positive components No. of ID-NAT positive donation 267 No. of components released 321 transfused ・・・・・・・・・・・ discarded ・・・・・・・・・・・ unknown ・・・・・・・・・・・ Outcome of transfused patients （ 191 reports available ） HBs-Ag conversion HBV-DNA conversion HBs-Ab conversion positive, but no information before transfusion 7 markers not changed dead discharged etc. 293 16 12 6 2 3 60 99 14

6. HBV infected Undetermined No change others 11 7 60 115 Infectious risk when transfused with ID-NAT positive blood 11 ／ 78 ～ 18 ／ 78 The infectivity of HBV-ID NAT-positive components 6 ～ 10 HBV infections per year

7. Infectivity of HBV ID-NAT positive components ComponentInfected No change totalinfectivity Window period (HBcAb -) 10213132% (10/31) Chronic carrier (HBcAb +) 139402.5% (1/40) Infectivity of W.P. component is 13 times as high as that from chronic carrier.

8. Implicated components component From window period From chronic carrier RBC 5 / 10 (50%) 0 / 19 FFP 3 / 10 (30%) 1 / 18 (6%) Platelet 2 / 4 (50%) 0 / 1

9. Established cases for HBV infection Disorders of patients hematologic malignancy2 gastric cancer2 dissecting aortic aneurysm 1 shock due to multiple trauma1 rheumatoid arthritis1 unknown4

10. ID-NAT in repository tubes --- voluntarily reported HBV cases ---

11. The risk of HBV infection under current screening algorism including 50p-NAT system SourcesHBV-infection Lookback investigation 6 ～ 10 Voluntary report of infection ５ total １ 1 ～１ 5 cases ／ year

12. Lookback study for HCV and HIV No. of ID-NAT performed No. of positive tubes HCV 4,371 2 (1 donation before NAT implementation) HIV 1,673 1 (Established infected case) Seroconversion possibly due to nonspecific reaction was also subjected to lookback study.

13. Estimates for the Occurrence of Transfusion- Transmitted 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 10 5 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 ）