[1] RIVM, Ctr Infect Dis Control, NL-3720 BA Bilthoven, Netherlands
[2] Univ Med Ctr Utrecht, Julius Ctr Hlth Sci & Primary Care, Utrecht, Netherlands
[3] European Ctr Dis Control, Stockholm, Sweden
[4] RIVM, Dept Prevent & Hlth Serv Res, NL-3720 BA Bilthoven, Netherlands