Norovirus has been on the rise since October, and the stomach virus is now positive in 12.4% of tests sent to labs, according to CDC data.
In December, norovirus rates peaked at 13% and has since hovered between 9.8% and 12.5%. The stomach bug that causes diarrhea and vomiting has a 13.4% positivity rate in the Northeast region, a 10.3% positivity rate in the Midwest, 12.1% in the West and 9.5% in the South.
In February 2023, there was a higher increase in norovirus infections, which spurred a rise in ED visits. Last year's peak was in March, with a 16.5% positivity rate.