[1] Statens Serum Inst, Ctr Vaccine Res, Dept Infect Dis Immunol, Copenhagen, Denmark
[2] Hvidovre Univ Hosp, Dept Infect Dis, Hvidovre, Denmark
[3] Univ Copenhagen, Inst Clin Med, Fac Hlth & Med Sci, Copenhagen, Denmark
[4] UCL, Div Infect & Immun, London, England