[1] Univ Helsinki, Haartman Inst, Dept Virol, FI-00290 Helsinki, Finland
[2] Univ Helsinki, Cent Hosp, Helsinki Univ Cent Hosp Lab, FI-00290 Helsinki, Finland
[3] Univ Helsinki, Cent Hosp, Dept Otorhinolaryngol, FI-00290 Helsinki, Finland
[4] Univ Helsinki, Cent Hosp, Dept Dermatol, FI-00290 Helsinki, Finland
[5] Dextra Med Ctr, FI-00350 Helsinki, Finland
[6] Cent Mil Hosp, FI-00300 Helsinki, Finland
[7] Natl Publ Hlth Inst, Dept Viral Dis & Immunol, FI-00300 Helsinki, Finland
[8] Univ Bonn, Inst Med Microbiol Immunol & Parasitol, D-53105 Bonn, Germany
[9] Univ Bonn, Inst Pathol, D-53105 Bonn, Germany
[10] Univ Bonn, Dept Surg, D-53105 Bonn, Germany