Christian Holm Hansen a, b , Ida Rask Moustsen-Helms a, Morten Rasmussen c, Bolette Søborg a, Henrik Ullum d, Palle Valentiner-Branth a
a Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Artillerivej 5, 2300 Kbh S, Denmark
b MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
c Virus Research and Development Laboratory, Virus & Microbiological Special Diagnostics, Statens Serum Institut, Copenhagen, Denmark
d Division of Infectious Disease Preparedness, Statens Serum Institut, Copenhagen, Denmark