Estimation of SARS-CoV-2 Infection Fatality Rate by Age and Comorbidity Status Using Antibody Screening of Blood Donors During the COVID-19 Epidemic in Denmark
Kathrine Agergård Kaspersen, Lotte Hindhede, Jens Kjærgaard Boldsen, Susan Mikkelsen, Lasse S Vestergaard, Ann-Sofie Nicole Berthelsen, Ida Rask Moustsen‐Helms, Dorte Kinggaard Holm, Anna Christine Nilsson, Susanne Gjørup Sækmose, Erik Sørensen, Lene Holm Harritshøj, Bitten Aagaard, Henrik Hjalgrim, Søren Thue Lillevang, Charlotte Sværke Jørgensen, Tyra Grove Krause, Henrik Ullum, Ole Birger Pedersen, Sisse Rye Ostrowski, Christian Erikstrup
Abstract
BACKGROUND: Studies presenting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection fatality rate (IFR) for healthy individuals are warranted. We estimate IFR by age and comorbidity status using data from a large serosurvey among Danish blood donors and nationwide data on coronavirus disease 2019 (COVID-19) mortality. METHODS: Danish blood donors aged 17-69 years donating blood October 2020-February 2021 were tested with a commercial SARS-CoV-2 total antibody assay. IFR was estimated for weeks 11 to 42, 2020 and week 43, 2020 to week 6, 2021, representing the first 2 waves of COVID-19 epidemic in Denmark. RESULTS: In total, 84944 blood donors were tested for antibodies. The seroprevalence was 2% in October 2020 and 7% in February 2021. Among 3898039 Danish residents aged 17-69 years, 249 deaths were recorded. The IFR was low for people <51 years without comorbidity during the 2 waves (combined IFR=3.36 per 100000 infections). The IFR was below 3‰ for people aged 61-69 years without comorbidity. IFR increased with age and comorbidity but declined from the first to second wave. CONCLUSIONS: In this nationwide study, the IFR was very low among people <51 years without comorbidity.