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This is a preprint article, it offers immediate access but has not been peer reviewed.
Posted: 21 Mar 2022
Winnie W.Y. Tso, MBBS1,2,*, Mike Y.W. Kwan, MBBS3,*, Yu Liang Wang, BSc1, Lok Kan Leung, MSocSc1, Daniel Leung,1, Gilbert T. Chua, MBBS1, Patrick Ip, MBBS1, Wilfred H.S. Wong, PhD1, Sophelia H.S. Chan, MBBS1, Jasper F.W. Chan, MD4, Malik Peiris, DPhil5, Yu Lung Lau, MD1,+, Jaime S. Rosa Duque, MD1,+
Abstract
Background: There has been a rapid surge of SARS-CoV-2 Omicron hospitalisations globally. However, the intrinsic severity of Omicron BA.2 is unknown, which could be determined by studying Hong Kong (HK) children who were both uninfected and unvaccinated before the Omicron wave.
Methods: This population-based study retrieved data from the HK territory-wide CDARS database of hospitalisations in all public hospitals and compared severe outcomes of the Omicron BA.2-dominant fifth wave (5 to 28 February 2022, n=1147), prior SARS-CoV-2 variants (1 January 2020 to 1 November 2021, n=737), and influenza and parainfluenza (1 January 2015 to 31 December 2019, n=32212 and n=16423, respectively) in children 0-11 years old. Outcomes included fatalities, paediatric intensive care unit (PICU) admissions and neurological and respiratory complications.
Findings: Four deaths (0.35%) occurred during the Omicron wave, resulting in a higher in-hospital case fatality rate than other SARS-CoV-2 variants (0%), influenza (0.05%) and parainfluenza (0.04%). PICU admission was higher for Omicron than other SARS-CoV-2 variants (OR=18.50, 95% CI 2.42-140.70, p=0.005) and influenza (OR=2.32, 95% CI 1.48-3.64, p<0.001). The proportion with neurological complications was 14.91% (171 out of 1,147) for Omicron, which was higher than influenza and parainfluenza (OR=1.75 95% CI 1.48-2.08 and OR=2.06 95% CI 1.74-2.46, p<0.001 for both, respectively). Croup occurred for Omicron more than other SARS-CoV-2 variants (OR=11.47, 95% CI 2.77-47.46 p = 0.001) and influenza (OR= 2.08, 95% CI 1.58-2.74 p<0.001) but not parainfluenza.
Interpretation: The intrinsic severity of Omicron BA.2 is not mild as evident by the fatality and severe complications of the uninfected and unvaccinated children.
Posted: 21 Mar 2022
Winnie W.Y. Tso, MBBS1,2,*, Mike Y.W. Kwan, MBBS3,*, Yu Liang Wang, BSc1, Lok Kan Leung, MSocSc1, Daniel Leung,1, Gilbert T. Chua, MBBS1, Patrick Ip, MBBS1, Wilfred H.S. Wong, PhD1, Sophelia H.S. Chan, MBBS1, Jasper F.W. Chan, MD4, Malik Peiris, DPhil5, Yu Lung Lau, MD1,+, Jaime S. Rosa Duque, MD1,+
Abstract
Background: There has been a rapid surge of SARS-CoV-2 Omicron hospitalisations globally. However, the intrinsic severity of Omicron BA.2 is unknown, which could be determined by studying Hong Kong (HK) children who were both uninfected and unvaccinated before the Omicron wave.
Methods: This population-based study retrieved data from the HK territory-wide CDARS database of hospitalisations in all public hospitals and compared severe outcomes of the Omicron BA.2-dominant fifth wave (5 to 28 February 2022, n=1147), prior SARS-CoV-2 variants (1 January 2020 to 1 November 2021, n=737), and influenza and parainfluenza (1 January 2015 to 31 December 2019, n=32212 and n=16423, respectively) in children 0-11 years old. Outcomes included fatalities, paediatric intensive care unit (PICU) admissions and neurological and respiratory complications.
Findings: Four deaths (0.35%) occurred during the Omicron wave, resulting in a higher in-hospital case fatality rate than other SARS-CoV-2 variants (0%), influenza (0.05%) and parainfluenza (0.04%). PICU admission was higher for Omicron than other SARS-CoV-2 variants (OR=18.50, 95% CI 2.42-140.70, p=0.005) and influenza (OR=2.32, 95% CI 1.48-3.64, p<0.001). The proportion with neurological complications was 14.91% (171 out of 1,147) for Omicron, which was higher than influenza and parainfluenza (OR=1.75 95% CI 1.48-2.08 and OR=2.06 95% CI 1.74-2.46, p<0.001 for both, respectively). Croup occurred for Omicron more than other SARS-CoV-2 variants (OR=11.47, 95% CI 2.77-47.46 p = 0.001) and influenza (OR= 2.08, 95% CI 1.58-2.74 p<0.001) but not parainfluenza.
Interpretation: The intrinsic severity of Omicron BA.2 is not mild as evident by the fatality and severe complications of the uninfected and unvaccinated children.
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