[1] Hlth Protect Agcy, Hlth Protect Serv, London NW9 5EQ, England
[2] European Publ Hlth Microbiol Fellowship Programme, Stockholm, Sweden
[3] St Lukes Hosp, Guardamangia, Malta
[4] Univ Genoa, Dept Hlth Sci, Genoa, Italy
[5] Natl Inst Res & Dev Microbiol & Immunol Cantacuzi, Natl Reference Ctr Viral Hepatitis, Natl Ctr Expertise Med Microbiol, Bucharest, Romania
[6] Ctr Communicable Dis & AIDS, Vilnius, Lithuania
[7] Natl Inst Hlth & Welf, Helsinki, Finland
[8] Univ Athens, Sch Med, Dept Hyg & Epidemiol, Natl Retrovirus Reference Ctr, GR-11527 Athens, Greece
[9] Robert Koch Inst, Berlin, Germany
[10] Natl Inst Publ Hlth, Prague, Czech Republic
[11] Inst Sanatate Publ Bucuresti, Bucharest, Romania
[12] Publ Hlth Author Slovak Republ, Natl Lab Poliomyelitis & Viral Hepatitis, Bratislava, Slovakia
[13] Inst Publ Hlth, Brussels, Belgium