In very young children, the Omicron variant of the coronavirus causes less severe disease than the Delta variant, according to a new study.
Researchers reviewed data on nearly 80,000 U.S. children under age 5 with a first infection, including 7,201 infected in late December or early January when Omicron was causing more than 90% of cases.
After accounting for other risk factors, including medical conditions and socioeconomic circumstances, researchers found children infected during the Omicron surge had a 29% lower risk of emergency department visits, a 67% lower risk of hospitalization, a 68% lower risk of needing intensive care, and a 71% lower risk of needing machines to breathe, compared to children infected with Delta.
However, “because of Omicron’s increased transmissibility, the overall number of emergency department visits, hospitalizations, ICU admissions, and mechanical ventilator use in kids may still be greater” with Omicron than with Delta, according to a report posted on medRxiv ahead of peer review.
The investigators have also observed that infection rates were disproportionately higher in Black and Hispanic children for both Omicron and Delta for this age group, and the gap widened for infections with Omicron, said study leader Rong Xu of Case Western Reserve University School of Medicine. Not yet published data shows that “children under 5 had the highest infection rate with Omicron” compared to older children and adults in all age groups, she said.