[1] Univ Athens, Sch Med, Dept Hyg & Epidemiol, Natl Retrovirus Reference Ctr, GR-11527 Athens, Goudi, Greece
[2] Natl Sch Publ Hlth, Athens, Greece
[3] Univ Ioannina, Sch Med, Dept Microbiol, GR-45110 Ioannina, Greece
[4] Laikon Gen Hosp, Blood Transfus Ctr 2, Athens, Greece
[5] Gen Athens Hosp G Gennimatas, Reg Blood Transfus Ctr 3, Athens, Greece
[6] Asklipeion Gen Hosp, Athens, Greece
[7] A Fleming Blood Transfus Ctr, Athens, Greece
[8] Elpis Gen Hosp, Athens, Greece
[9] N Ionia Gen Hosp, Athens, Greece