Boston-Area Sewage Shows Continued Drop In Coronavirus

BOSTON — Coronavirus in the Boston-area wastewater continued its decline through Wednesday, according to the latest data published by Cambridge-based epidemiology firm Biobot Analytics.

The amount of viral RNA in Deer Island Treatment Plant sewage remains above the pre-omicron maximum, it peaked from Jan. 3-5 and began to fall as quickly as it rose.

The fall continued in a new sample taken Tuesday, according to Biobot data, although the rate of decline appears to have slowed.

The plant serves 43 communities in greater Boston. Samples of wastewater are taken three to seven times a week, according to the Massachusetts Water Resources Authority.

The samples are split between the authority's "North System" and "South System," which each contain part of Boston and surrounding communities. A map of the North and South systems is available here.

>>MA Coronavirus Positive Rate Drops On 'Backside' Of Omicron Surge

According to the Centers for Disease Control and Prevention, the wastewater metric "can provide information on changes in total SARS-CoV-2 (COVID-19) infection in the community contributing to that wastewater treatment plant." In other words, an increased presence of COVID-19 in wastewater from showers, sinks and toilets can indicate an increased infection rate in the communities where the wastewater comes from.

"Every time an infected person uses the toilet, they're flushing this information down the toilet, where it's collecting and aggregating and mixing with poop from thousands of other people," Newsha Ghaeli, a co-founder and president of Biobot Analytics, told NBC News.

The wastewater data has predicted trends in other coronavirus metrics in recent weeks, with the positive rate and even hospitalizations now also showing the state is over the worst of the omicron surge.

This article originally appeared on the Boston Patch