Overview
- WasteWaterSCAN classified national norovirus activity as high for the week ending Dec. 12, and CDC data show 9.37% test positivity for the week ending Dec. 6 after a steady autumn rise.
- Los Angeles County reported rapid wastewater increases, with detections up 154% in the city and more than 250% countywide over three weeks, according to health officials.
- Michigan wastewater data indicate rising transmission since October, with five of six monitored communities in the high category, including Jackson, Jenison, Mt. Pleasant, Traverse City, and Warren.
- Health guidance emphasizes thorough handwashing with soap and water and disinfecting with EPA List G products or diluted bleach, noting many wipes are less effective against norovirus.
- Officials warn the virus can aerosolize during vomiting, contaminate surfaces for weeks, and remain contagious for up to two days after symptoms resolve, reinforcing careful cleanup and hygiene.