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

Aliquots from all donations have been stored since 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

ID-NAT results in repository tubes from seroconverted or NAT-converted donors No. of ID-NAT performed No. of positive tubes Positivity rate (%) HBV20, HCV4, HIV1, total 26, (‘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 %3.0 HB ｓ -Ag ％ 4.6 HB ｃ -Ab %32.6 total ％ 40.2 These donations do not directly relate to infectivity.

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

HBV infected Undetermined No change others 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

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

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

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

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

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

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.

Estimates for the Occurrence of Transfusion- Transmitted Viral Diseases in Japan HBV HBV+ donation detectable only by ID-NAT : 1 / 150, ～ 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 ）