Early Spread of SARS-Cov-2 in the Icelandic Population

Daniel F Gudbjartsson; Agnar Helgason; Hakon Jonsson; Olafur T Magnusson; Pall Melsted; Gudmundur L Norddahl; Jona Saemundsdottir; Asgeir Sigurdsson; Patrick Sulem; Arna B Agustsdottir; Berglind Eiriksdottir; Run Fridriksdottir; Elisabet E Gardarsdottir; Gudmundur Georgsson; Olafia S Gretarsdottir; Kjartan R Gudmundsson; Thora R Gunnarsdottir; Arnaldur Gylfason; Hilma Holm; Brynjar O Jensson; Aslaug Jonasdottir; Frosti Jonsson; Kamilla S Josefsdottir; Thordur Kristjansson; Droplaug N Magnusdottir; Louise le Roux; Gudrun Sigmundsdottir; Gardar Sveinbjornsson; Kristin E Sveinsdottir; Maney Sveinsdottir; Emil A Thorarensen; Bjarni Thorbjornsson; Arthur Love; Gisli Masson; Ingileif Jonsdottir; Alma Moller; Thorolfur Gudnason; Karl G Kristinsson; Unnur Thorsteinsdottir; Kari Stefansson

To further our understanding of the spread of the virus and to determine how the virus mutates as it spreads, we sequenced the virus from 357 individuals who had tested positive before March 19. The haplotype composition of the viruses from individuals identified through the population screening was different from those tested in the early targeted testing; more had the A1a haplotype and fewer had the A2a haplotypes. Hence, it looks like the haplotypes of the virus that are propagating in the general population come from a different source, perhaps brought in by people coming from countries that had not yet been designated high-risk areas. Furthermore, the sequence diversity in the virus from the population screening is greater than in the original targeted screening that was focused on people coming home from skiing in the Alps. Hence, it is likely that the virus has been carried into Iceland from many countries. The 0.9% frequency of the infection in the population screening indicates that the virus is spreading to the extent that unless we increase the screening effort we are likely to fail in our efforts to contain it.