Omicron was probably in N.Y.C. well before the first U.S. case was detected, wastewater data suggest.

The samples suggest that someone in New York City may have had the Omicron variant as early as Nov. 21, four days before South African scientists first announced cases of the variant and ten days before the first U.S. case was reported. Researchers in California and Texas also found evidence of Omicron in wastewater samples from late November.

The article reports on a recent article published in the CDC’s Morbidity and Mortality Weekly Report .