TY - JOUR
T1 - Age-specific severity of severe acute respiratory syndrome coronavirus 2 in February 2020 to June 2021 in the Netherlands
AU - de Boer, Pieter T.
AU - van de Kassteele, Jan
AU - Vos, Eric R. A.
AU - van Asten, Liselotte
AU - Dongelmans, Dave A.
AU - van Gageldonk-Lafeber, Arianne B.
AU - den Hartog, Gerco
AU - Hofhuis, Agnetha
AU - van der Klis, Fiona
AU - de Lange, Dylan W.
AU - Stoeldraijer, Lenny
AU - de Melker, Hester E.
AU - Geubbels, Eveline
AU - van den Hof, Susan
AU - the RIVM COVID-19 epidemiology and surveillance team
AU - Wallinga, Jacco
N1 - Funding Information: This work was supported by the Netherlands Ministry of Health, Welfare and Sport. This project has received funding from the European Union's Horizon 2020 research and innovation program—project EpiPose (grant agreement number 101003688). Funding Information: We thank the members of the RIVM COVID-19 surveillance and epidemiology team for the handling of data from various sources used in this manuscript. We gratefully acknowledge the participants of the serology study (PIENTER Corona) and the contribution of colleagues from the department of Immunology of Infectious Diseases and Vaccines (IIV) of RIVM for the laboratory analyses of the serology samples. We thank the National Intensive Care Evaluation (NICE) foundation for providing data on hospitalizations and ICU admissions and Nicolette de Keizer of NICE for commenting on the manuscript. We thank Statistics Netherlands for providing all-cause mortality data by specified age group. Publisher Copyright: © 2023 The Authors. Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.
PY - 2023/8/1
Y1 - 2023/8/1
N2 - Background: The severity of Severe Acute Respiratory Syndrome Coronavirus 2 infection varies with age and time. Here, we quantify how age-specific risks of hospitalization, intensive care unit (ICU) admission, and death upon infection changed from February 2020 to June 2021 in the Netherlands. Methods: A series of large representative serology surveys allowed us to estimate age-specific numbers of infections in three epidemic periods (late-February 2020 to mid-June 2020, mid-June 2020 to mid-February 2021, and mid-February 2021 to late-June 2021). We accounted for reinfections and breakthrough infections. Severity measures were obtained by combining infection numbers with age-specific numbers of hospitalization, ICU admission, and excess all-cause deaths. Results: There was an accelerating, almost exponential, increase in severity with age in each period. The rate of increase with age was the highest for death and the lowest for hospitalization. In late-February 2020 to mid-June 2020, the overall risk of hospitalization upon infection was 1.5% (95% confidence interval [CI] 1.3–1.8%), the risk of ICU admission was 0.36% (95% CI: 0.31–0.42%), and the risk of death was 1.2% (95% CI: 1.0–1.4%). The risk of hospitalization was significantly increased in mid-June 2020 to mid-February 2021, while the risk of ICU admission remained stable over time. The risk of death decreased over time, with a significant drop among ≥70-years-olds in mid-February 2021 to late-June 2021; COVID-19 vaccination started early January 2021. Conclusion: Whereas the increase in severity of Severe Acute Respiratory Syndrome Coronavirus 2 with age remained stable, the risk of death upon infection decreased over time. A significant drop in risk of death among elderly coincided with the introduction of COVID-19 vaccination.
AB - Background: The severity of Severe Acute Respiratory Syndrome Coronavirus 2 infection varies with age and time. Here, we quantify how age-specific risks of hospitalization, intensive care unit (ICU) admission, and death upon infection changed from February 2020 to June 2021 in the Netherlands. Methods: A series of large representative serology surveys allowed us to estimate age-specific numbers of infections in three epidemic periods (late-February 2020 to mid-June 2020, mid-June 2020 to mid-February 2021, and mid-February 2021 to late-June 2021). We accounted for reinfections and breakthrough infections. Severity measures were obtained by combining infection numbers with age-specific numbers of hospitalization, ICU admission, and excess all-cause deaths. Results: There was an accelerating, almost exponential, increase in severity with age in each period. The rate of increase with age was the highest for death and the lowest for hospitalization. In late-February 2020 to mid-June 2020, the overall risk of hospitalization upon infection was 1.5% (95% confidence interval [CI] 1.3–1.8%), the risk of ICU admission was 0.36% (95% CI: 0.31–0.42%), and the risk of death was 1.2% (95% CI: 1.0–1.4%). The risk of hospitalization was significantly increased in mid-June 2020 to mid-February 2021, while the risk of ICU admission remained stable over time. The risk of death decreased over time, with a significant drop among ≥70-years-olds in mid-February 2021 to late-June 2021; COVID-19 vaccination started early January 2021. Conclusion: Whereas the increase in severity of Severe Acute Respiratory Syndrome Coronavirus 2 with age remained stable, the risk of death upon infection decreased over time. A significant drop in risk of death among elderly coincided with the introduction of COVID-19 vaccination.
KW - COVID-19
KW - SARS-CoV-2
KW - disease severity
KW - epidemiology
KW - infection fatality ratio
UR - http://www.scopus.com/inward/record.url?scp=85168589735&partnerID=8YFLogxK
U2 - https://doi.org/10.1111/irv.13174
DO - https://doi.org/10.1111/irv.13174
M3 - Article
C2 - 37621921
SN - 1750-2640
VL - 17
JO - Influenza and other respiratory viruses
JF - Influenza and other respiratory viruses
IS - 8
M1 - e13174
ER -