COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022

Abstract Background Coronavirus disease 2019 (COVID-19) burden is difficult to quantify with cases missed by surveillance systems. During COVID-19 Delta and Omicron BA.1–5 periods, we assessed the COVID-19 burden in New South Wales (NSW), Australia, from May 2021–July 2022 using a participatory surv...

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Main Authors: Kelsey M. Sumner, Sandra Carlson, Benjamin Elton, Michelle Butler, Janaki Amin, Melissa A. Rolfes, Carrie Reed, A. Danielle Iuliano, David J. Muscatello, Craig Dalton
Format: Article
Language:English
Published: BMC 2025-03-01
Series:BMC Public Health
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Online Access:https://doi.org/10.1186/s12889-025-22021-x
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author Kelsey M. Sumner
Sandra Carlson
Benjamin Elton
Michelle Butler
Janaki Amin
Melissa A. Rolfes
Carrie Reed
A. Danielle Iuliano
David J. Muscatello
Craig Dalton
author_facet Kelsey M. Sumner
Sandra Carlson
Benjamin Elton
Michelle Butler
Janaki Amin
Melissa A. Rolfes
Carrie Reed
A. Danielle Iuliano
David J. Muscatello
Craig Dalton
author_sort Kelsey M. Sumner
collection DOAJ
description Abstract Background Coronavirus disease 2019 (COVID-19) burden is difficult to quantify with cases missed by surveillance systems. During COVID-19 Delta and Omicron BA.1–5 periods, we assessed the COVID-19 burden in New South Wales (NSW), Australia, from May 2021–July 2022 using a participatory surveillance system of self-reported respiratory disease and a database of people seeking healthcare. Methods To estimate community illness burden, we adjusted the NSW age-stratified non-case population by reported severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) percent positive and acute respiratory illness (ARI) rates. Hospitalization and death burden were estimated by adjusting reported rates to the NSW population and by the proportion of COVID-19 admissions attributable to COVID-19 illness. Burden estimates were compared to reported case counts. Results From May 2021–July 2022, an estimated 3,450,516 (95%CI: 2,847,355–4,119,472) symptomatic community ARI illnesses, 24,684 (95%CI: 20,714–29,144) hospitalizations, and 4,638 (95% CI: 3,263–6,049) deaths were attributable to COVID-19 in NSW. Reported cases (3,039,239) were 14% lower than the estimated symptomatic community illness burden but within the estimate’s 95% confidence interval. Overall, 0.7% of symptomatic community illnesses resulted in hospitalization and 0.1% resulted in death. Conclusions Estimated symptomatic case hospitalization and fatality risk could be used for COVID-19 modelling and forecasting.
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spelling doaj-art-17dde90ccedd48f3a3c05276f6e9529f2025-08-20T02:49:12ZengBMCBMC Public Health1471-24582025-03-0125111010.1186/s12889-025-22021-xCOVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022Kelsey M. Sumner0Sandra Carlson1Benjamin Elton2Michelle Butler3Janaki Amin4Melissa A. Rolfes5Carrie Reed6A. Danielle Iuliano7David J. Muscatello8Craig Dalton9Influenza Division, Centers for Disease Control and PreventionPopulation Health, Hunter New England Local Health DistrictPopulation Health, Hunter New England Local Health DistrictPopulation Health, Hunter New England Local Health DistrictHealth Protection New South Wales, Ministry of Health, North SydneyInfluenza Division, Centers for Disease Control and PreventionInfluenza Division, Centers for Disease Control and PreventionInfluenza Division, Centers for Disease Control and PreventionSchool of Population Health, University of New South WalesPopulation Health, Hunter New England Local Health DistrictAbstract Background Coronavirus disease 2019 (COVID-19) burden is difficult to quantify with cases missed by surveillance systems. During COVID-19 Delta and Omicron BA.1–5 periods, we assessed the COVID-19 burden in New South Wales (NSW), Australia, from May 2021–July 2022 using a participatory surveillance system of self-reported respiratory disease and a database of people seeking healthcare. Methods To estimate community illness burden, we adjusted the NSW age-stratified non-case population by reported severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) percent positive and acute respiratory illness (ARI) rates. Hospitalization and death burden were estimated by adjusting reported rates to the NSW population and by the proportion of COVID-19 admissions attributable to COVID-19 illness. Burden estimates were compared to reported case counts. Results From May 2021–July 2022, an estimated 3,450,516 (95%CI: 2,847,355–4,119,472) symptomatic community ARI illnesses, 24,684 (95%CI: 20,714–29,144) hospitalizations, and 4,638 (95% CI: 3,263–6,049) deaths were attributable to COVID-19 in NSW. Reported cases (3,039,239) were 14% lower than the estimated symptomatic community illness burden but within the estimate’s 95% confidence interval. Overall, 0.7% of symptomatic community illnesses resulted in hospitalization and 0.1% resulted in death. Conclusions Estimated symptomatic case hospitalization and fatality risk could be used for COVID-19 modelling and forecasting.https://doi.org/10.1186/s12889-025-22021-xCOVID-19SARS-CoV-2Burden estimationCase fatality riskCase hospitalization risk
spellingShingle Kelsey M. Sumner
Sandra Carlson
Benjamin Elton
Michelle Butler
Janaki Amin
Melissa A. Rolfes
Carrie Reed
A. Danielle Iuliano
David J. Muscatello
Craig Dalton
COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
BMC Public Health
COVID-19
SARS-CoV-2
Burden estimation
Case fatality risk
Case hospitalization risk
title COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
title_full COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
title_fullStr COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
title_full_unstemmed COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
title_short COVID-19 symptomatic community illness, hospitalization, and death burden across all ages — New South Wales, Australia, May 2021–July 2022
title_sort covid 19 symptomatic community illness hospitalization and death burden across all ages new south wales australia may 2021 july 2022
topic COVID-19
SARS-CoV-2
Burden estimation
Case fatality risk
Case hospitalization risk
url https://doi.org/10.1186/s12889-025-22021-x
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