Among children under age 5 who were ineligible for coronavirus vaccines, the Omicron variant caused 6- to 8-times more infections than the Delta variant, but severe COVID-19 was less common with Omicron, U.S. researchers found.
They reviewed data collected in 2021 and early 2022 on 651,640 children younger than age 5, including 66,692 with Delta infections and 22,772 with Omicron infections. When Delta was predominant, two to three children among every 2,000 became infected every day, the researchers calculated.
When Omicron first started to circulate, that rate rose to roughly five to 13 new infections per day among every 2,000 children, the researchers reported in JAMA Pediatrics. By mid-January 2022, more than 16 of every 2,000 small children were becoming infected with Omicron every day, with the highest infection rates seen in children under age 2.
Children infected with Omicron, however, were at significantly lower risk for severe disease compared to similar children infected with Delta. The findings may aid considerations about school attendance, mask use, and vaccine implementation for young children, the research team said.