Article
作者: Gudbjartsson, D. F. ; Norddahl, G. L. ; Melsted, P. ; Gunnarsdottir, K. ; Holm, H. ; Eythorsson, E. ; Arnthorsson, A. O. ; Helgason, D. ; Bjarnadottir, K. ; Ingvarsson, R. F. ; Thorsteinsdottir, B. ; Kristjansdottir, S. ; Birgisdottir, K. ; Kristinsdottir, A. M. ; Sigurdsson, M. I. ; Arnadottir, G. A. ; Ivarsdottir, E. V. ; Andresdottir, M. ; Jonsson, F. ; Agustsdottir, A. B. ; Berglund, J. ; Eiriksdottir, B. ; Fridriksdottir, R. ; Gardarsdottir, E. E. ; Gottfredsson, M. ; Gretarsdottir, O. S. ; Gudmundsdottir, S. ; Gudmundsson, K. R. ; Gunnarsdottir, T. R. ; Gylfason, A. ; Helgason, A. ; Jensson, B. O. ; Jonasdottir, A. ; Jonsson, H. ; Kristjansson, T. ; Kristinsson, K. G. ; Magnusdottir, D. N. ; Magnusson, O. T. ; Olafsdottir, L. B. ; Rognvaldsson, S. ; le Roux, L. ; Sigmundsdottir, G. ; Sigurdsson, A. ; Sveinbjornsson, G. ; Sveinsdottir, K. E. ; Sveinsdottir, M. ; Thorarensen, E. A. ; Thorbjornsson, B. ; Thordardottir, M. ; Saemundsdottir, J. ; Kristjansson, S. H. ; Josefsdottir, K. S. ; Masson, G. ; Georgsson, G. ; Kristjansson, M. ; Moller, A. ; Palsson, R. ; Gudnason, T. ; Thorsteinsdottir, U. ; Jonsdottir, I. ; Sulem, P. ; Stefansson, K.
BACKGROUND:Little is known about the nature and durability of the humoral immune response to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
METHODS:We measured antibodies in serum samples from 30,576 persons in Iceland, using six assays (including two pan-immunoglobulin [pan-Ig] assays), and we determined that the appropriate measure of seropositivity was a positive result with both pan-Ig assays. We tested 2102 samples collected from 1237 persons up to 4 months after diagnosis by a quantitative polymerase-chain-reaction (qPCR) assay. We measured antibodies in 4222 quarantined persons who had been exposed to SARS-CoV-2 and in 23,452 persons not known to have been exposed.
RESULTS:Of the 1797 persons who had recovered from SARS-CoV-2 infection, 1107 of the 1215 who were tested (91.1%) were seropositive; antiviral antibody titers assayed by two pan-Ig assays increased during 2 months after diagnosis by qPCR and remained on a plateau for the remainder of the study. Of quarantined persons, 2.3% were seropositive; of those with unknown exposure, 0.3% were positive. We estimate that 0.9% of Icelanders were infected with SARS-CoV-2 and that the infection was fatal in 0.3%. We also estimate that 56% of all SARS-CoV-2 infections in Iceland had been diagnosed with qPCR, 14% had occurred in quarantined persons who had not been tested with qPCR (or who had not received a positive result, if tested), and 30% had occurred in persons outside quarantine and not tested with qPCR.
CONCLUSIONS:Our results indicate that antiviral antibodies against SARS-CoV-2 did not decline within 4 months after diagnosis. We estimate that the risk of death from infection was 0.3% and that 44% of persons infected with SARS-CoV-2 in Iceland were not diagnosed by qPCR.