[1] Hlth Protect Agcy, Ctr Infect, HIV & STI Dept, London, England
[2] European Ctr Dis Prevent & Control ECDC, Stockholm, Sweden
[3] Inst Veille Sanit, St Maurice, France
[4] RIVM, Bilthoven, Netherlands
[5] Robert Koch Inst, D-1000 Berlin, Germany
[6] Sci Inst Publ Hlth, Brussels, Belgium
[7] Statens Serum Inst, DK-2300 Copenhagen, Denmark
[8] Inst Salud Carlos III, Madrid, Spain
[9] Inst Nacl Saude Dr Ricardo Jorge, Lisbon, Portugal