Emerg Microbes Infect . Severity of SARS-CoV-2 Omicron BA.2 infection in unvaccinated hospitalized children: Comparison to influenza and parainfluenza infections

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Emerg Microbes Infect


. 2022 Jun 22;1-29.
doi: 10.1080/22221751.2022.2093135. Online ahead of print.
Severity of SARS-CoV-2 Omicron BA.2 infection in unvaccinated hospitalized children: Comparison to influenza and parainfluenza infections


Winnie W Y Tso MBBS ^{1 2} , Mike Y W Kwan MBBS,MSc ³ , Yu Liang Wang BSc ¹ , Lok Kan Leung MSocSc ¹ , Daniel Leung ¹ , Gilbert T Chua MBBS ¹ , Patrick Ip MBBS ¹ , Daniel Y T Fong PhD ⁴ , Wilfred H S Wong PhD ¹ , Sophelia H S Chan MBBS ¹ , Jasper F W Chan MD ⁵ , Malik Peiris DPhil ⁶ , Yu Lung Lau MBChB,MD(Hon) ¹ , Jaime S Rosa Duque MD,PhD ¹



Affiliations

• PMID: 35730665
• DOI: 10.1080/22221751.2022.2093135

Abstract

AbstractThere has been a rapid surge of hospitalization due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variants globally. The severity of Omicron BA.2 in unexposed, unvaccinated, hospitalized children is unknown. We investigated the severity and clinical outcomes of COVID-19 infection during the Omicron wave in uninfected, unvaccinated hospitalized children and in comparison with influenza and parainfluenza viral infections. This population-based study retrieved data from the HK territory-wide CDARS database of hospitalisations in all public hospitals and compared severe outcomes for the Omicron BA.2-dominant fifth wave (5 to 28 February 2022, n = 1144), and influenza and parainfluenza viruses (1 January 2015 to 31 December 2019, n = 32212 and n = 16423, respectively) in children 0-11 years old. Two deaths (0.2%) out of 1144 cases during the initial Omicron wave were recorded. Twenty-one (1.8%) required PICU admission, and the relative risk was higher for Omicron than influenza virus (n = 254, 0.8%, adjusted RR = 2.1, 95%CI 1.3-3.3, p = 0.001). The proportion with neurological complications was 15.0% (n = 171) for Omicron, which was higher than influenza and parainfluenza viruses (n = 2707, 8.4%, adjusted RR = 1.6, 95%CI 1.4-1.9 and n = 1258, 7.7%, adjusted RR = 1.9, 95%CI 1.6-2.2, p < 0.001 for both, respectively). Croup occurred for Omicron (n = 61, 5.3%) more than influenza virus (n = 601, 1.9%, adjusted RR = 2.0, 95%CI 1.5-2.6, p < 0.001) but not parainfluenza virus (n = 889, 5.4%). Our findings showed that for hospitalized children who had no past COVID-19 or vaccination, Omicron BA.2 was not mild. Omicron BA.2 appeared to be more neuropathogenic than influenza and parainfluenza viruses. It targeted the upper airways more than influenza virus.

Keywords: COVID-19; Omicron; children; neurological; respiratory.