Extreme outcomes in hospitalized youngsters throughout the Omicron BA.2-dominated fifth wave in Hong Kong

A current examine posted to Preprints with The Lancet* investigated the illness severity of extreme acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron BA.2 an infection amongst Hong Kong youngsters.

Study: Intrinsic Severity of SARS-CoV-2 Omicron BA.2 in Uninfected, Unvaccinated Children: A Population-Based, Case-Control Study on Hospital Complications. Image Credit: Beenicebeelove/Shutterstock
Examine: Intrinsic Severity of SARS-CoV-2 Omicron BA.2 in Uninfected, Unvaccinated Youngsters: A Inhabitants-Based mostly, Case-Management Examine on Hospital Problems. Picture Credit score: Beenicebeelove/Shutterstock


Earlier than the coronavirus illness 2019 (COVID-19) vaccination program commenced in the UK (UK), greater than 469,900 youngsters underneath 18 years had been recognized with COVID-19, with 5 fatalities per 100,000 youngsters. COVID-19 has killed greater than six million folks, and pediatric deaths represent about 0.4%. SARS-CoV-2 Omicron, the not too long ago emerged variant of concern (VOC), has prompted the newest surge in COVID-19 instances worldwide.

Though the illness severity with Omicron infections is reportedly milder in these protected against earlier an infection or immunization or each, it might not maintain true for these (youngsters) who’re but to be vaccinated.

Hong Kong, which has enforced stringent COVID-19-related measures for the reason that onset of the COVID-19 pandemic, has been witnessing an alarming surge of infections currently. Hong Kong had recorded simply over 14,000 instances earlier than the emergence of the Omicron variant. Nonetheless, infections soared to file highs, and greater than 0.9 new million instances have been reported between December 31st, 2021, and March 15th, 2022. Many research recommend that SARS-CoV-2 Omicron may not simply trigger milder infections as beforehand speculated.

The examine

The researchers of the current population-based, case-control examine evaluated the illness outcomes in Hong Kong youngsters hospitalized with COVID-19. Youngsters aged 11 years or beneath hospitalized between February 5 and 28, 2022 (an Omicron BA.2-dominant interval) have been studied, who lacked prior immunity as Hong Kong started vaccination of 5 to 11-year-olds in mid-January 2022.

Digital medical information obtained from the medical knowledge evaluation and reporting system (CDARS) within the specified interval have been reviewed. Moreover, hospitalization knowledge of SARS-CoV-2-infected youngsters have been extracted between January 1st, 2021, and November 1st, 2021 (pre-Omicron interval). Lastly, influenza and parainfluenza-associated baby hospitalization knowledge between 2015 and 2019 have been additionally retrieved. These coinfected with two or extra respiratory viruses have been excluded from the examine.

The extracted knowledge have been categorized into the next courses– 1) fatality and extreme, 2) neurological, and three) respiratory issues. Fatality and extreme issues have been labeled based mostly on the case fatality charge (CFR), pediatric intensive care (PICU) admissions, mechanical air flow, and oxygen use. These with neurological issues have been stratified into seizures and encephalitis or encephalopathy sub-classes. Youngsters have been additional grouped based mostly on respiratory issues like croup or pneumonia. Odds ratios (OR) for the desired outcomes have been calculated utilizing binary logistic regression evaluation.


Within the interval between February 5th and 28th, 2022, about 1147 youngsters have been hospitalized on account of Omicron infections, of which 80.21% have been aged underneath 5 years. Earlier than November 1st, 2021, 737 youngsters have been hospitalized with SARS-CoV-2 an infection. Throughout the interval between 2015 and 2019, round 32,212 and 16,423 baby hospitalizations have been on account of influenza and parainfluenza infections, respectively. Within the Omicron-dominant wave, 4 youngsters died on account of COVID-19.

Two deaths have been attributed to their neurological issues – considered one of them had encephalopathy, and the opposite had fulminant cerebral edema, a not too long ago acknowledged encephalitis phenotype. Nevertheless, COVID-19-related deaths weren’t noticed within the pre-Omicron interval. CFR of COVID-19 throughout Omicron surge (0.35%) was increased than that of influenza (0.05%) and parainfluenza (0.04%) infections. PICU admissions have been increased throughout the Omicron surge (1.83%) than in pre-Omicron waves (0.14%) and the 5 years (2015 to 2019) on account of influenza (0.79%) and parainfluenza (1.64%). The percentages of PICU admissions have been increased within the Omicron interval than earlier COVID-19 waves and influenza however much like parainfluenza instances.

Throughout the Omicron-dominant interval, 171 hospitalized youngsters had neurological issues, the commonest being febrile seizure with 11.6% incidence. Earlier than the Omicron interval, there have been no seizure instances in COVID-19-hospitalized youngsters. Furthermore, the percentages of all forms of seizures amongst youngsters with Omicron infections have been increased than these with influenza and parainfluenza. Sixty-one (5.32%) youngsters contaminated with the SARS-CoV-2 Omicron variant developed croup in comparison with two (0.27%) contaminated with earlier SARS-CoV-2 variants, 601 (1.87) with influenza, and 889 (5.41%) with parainfluenza. The incidence of pneumonia in youngsters on account of SARS-CoV-2 Omicron was much like these contaminated with earlier variants however decrease in influenza and parainfluenza instances.


The examine findings confirmed that SARS-CoV-2 Omicron BA.2 infections resulted in additional baby hospitalizations within the 23 days of the examine than 22 months earlier than. This indicated that the BA.2 variant of SARS-CoV-2 Omicron was extra pathogenic than prior SARS-CoV-2 variants and influenza virus and advised that youngsters be vaccinated to stop extreme outcomes.

One notable limitation of the examine was the dearth of viral genome sequencing knowledge verifying that each one infections in February 2022 have been prompted solely by the SARS-CoV-2 Omicron BA.2 variant. Nonetheless, epidemiological knowledge point out the preponderance of the Omicron variant proper from the beginning of the newest surge.

*Vital discover

Preprints with The Lancet publish preliminary scientific stories that aren’t peer-reviewed and, subsequently, shouldn’t be considered conclusive, information medical follow/health-related habits, or handled as established data.

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