New research from the Case Western Reserve University (CWRU) School of Medicine shows that children under the age of 5 infected with the Omicron variant of COVID-19 have a lower risk of serious health consequences than those infected with the Delta variant.
The study was published Friday in JAMA Pediatrics, is the first large-scale study to compare the health outcomes of coronavirus infections in children 4 years and younger (an unvaccinated age group) from Omicron to Delta.
The findings showed that the Omicron variant was 6-8 times more infectious than the Delta variant. Serious clinical outcomes ranged from a 16% reduction in the risk of emergency room visits to an 85% reduction in the risk of mechanical ventilation. About 1.8% of children infected with Omicron were hospitalized, compared with 3.3% for Delta.
The Case Western Reserve-led team analyzed the electronic health records of more than 651,640 U.S. children who visited a healthcare facility between September 20, 2021 and January 2022, including more than 22,772 who contracted Omicron in late to late December Children’s January – When delta hits in the fall, more than 66,000 children are infected. The study also compared records from more than 10,000 children in the U.S. before Omicron was detected, but when Delta was still dominant.
Children under the age of 5 are not yet eligible for the COVID-19 vaccine and have low prior SARS-CoV-2 infection rates, which also limits their pre-existing immunity.
The team examined clinical health outcomes in pediatric patients within a 14-day window following SARS-CoV-2 infection. Factors they reviewed included: emergency room visits, hospitalizations, ICU admissions, and use of mechanical ventilation.
Further demographic data analysis found that children infected with Omicron were younger on average — 1.5 years versus 1.7 years — and had fewer comorbidities.
“The main conclusion of our study is that more children were infected with Omicron than Delta, but the children who were infected were not as badly affected as children who were infected with the Delta variant,” said Arline H. and Case Western Reserve School of Medicine. Curtis F. Garvin Research Professor. “However, our hospitals were affected by the influx of children during the winter months as more children became infected.”
“We saw a surge in hospitalizations in this age group in January this year because the infection rate of Omicron was about 10 to 15 times higher than that of the Delta variant,” said Rong Xu, professor and director of biomedical informatics. Center for Artificial Intelligence in Drug Discovery, School of Medicine. “Omicron is not as severe as Delta, however, the severity of clinical outcomes ranged from only 16% to 85%. In addition, with so many unvaccinated children infected, COVID-19 infection affects children’s brain, heart, immune system and other Organs remain unknown and worrying.”
The CDC recommends that people 5 years and older get the COVID-19 vaccine, and those 12 years and older who are fully vaccinated receive a booster shot. In counties with a low or moderate “Covid-19 community level,” Americans no longer need to wear masks indoors, according to the latest CDC guidance.