March 19, 2024 -- COVID-19 may be headed toward a springtime retreat.
The indication comes from declining levels of SARS-CoV-2 -- the virus that causes COVID -- being detected in wastewater over the past 3 weeks. Virus levels are already considered “low” throughout western U.S. states. Detections are at medium levels in the Midwest and South, while high levels persist in the Northeast, according to WastewaterSCAN.
But it’s not time to let your guard down because high levels of other viruses that cause stomach and respiratory illnesses continue to circulate widely nationwide. Wastewater data currently shows threats from flu, RSV, norovirus, and rotavirus.
The rate of positive flu tests reported to the CDC had been a downward trend since peaking around a rate of 16% in mid-January, but positive test rates are now climbing again, with the most recent weekly rate back around 15%. So far this flu season, 116 children and an estimated 20,000 adults have died from the flu, according to the CDC’s weekly flu publication, FluView.
RSV wastewater detection remains high, especially in the Midwest and Northeast, WastewaterSCAN data shows. But positive RSV test results reported to the CDC are at the lowest point of the 2023 to 2024 season, with less than 2,000 positive results listed for the week of March 9, down from a peak of more than 14,000 cases around Christmas.
Wastewater data tends to offer a real-time (and sometimes predictive) view of pathogen behavior in the general population, since sick people usually wait until symptoms worsen to seek medical care. About 12% of norovirus tests reported to the CDC in the last 3 weeks of February were positive, mirroring an upward trend observed during the same time period last year. In 2023, norovirus peaked in the U.S. in March with a positive test rate around 16%, CDC data show.
Last year, COVID also followed a downward springtime trend. Around this time last year, there were about 20,000 weekly hospital admissions due to COVID-19, compared to just over 13,000 in early March this year. All COVID metrics, including the positive test rate, hospitalizations, and ER visits, are currently trending downward, the CDC’s COVID Data Tracker indicates. The positive COVID test rate is 5%, and just 1% of ER visits in the U.S. involve a COVID-19 diagnosis.
“We’re seeing a downward trend, which is fantastic,” Marlene Wolfe, PhD, WastewaterSCAN’s program director, told USA Today. “Hopefully, that pattern continues as we enjoy some warmer weather and longer daylight.”