Traces of coronavirus in waste water tick upward again

A man gets a coronavirus test at a mobile testing site on Blue Hill Avenue in BostonSuzanne Kreiter/Globe staff

The amount of coronavirus detected in the waste water at the Massachusetts Water Resources Authority’s Deer Island treatment plant dipped after a startling rise two weeks ago, but is now ticking upward again.

The results, which include tests conducted up to Monday, showed the northern section of the MWRA system, which includes Boston, reaching the highest level yet of a recent surge. The southern section was on the rise again, though still short of a spike it reached around Oct. 25.

The program, which looks for SarsCOV2 RNA copies in waste water, is a pilot that officials hope can provide early warning of virus surges.

Coronavirus traces in waste water at the Deer Island treatment plant are ticking up againMWRA

The MWRA had been testing several times a week, but in mid-October state officials, noting increases, asked the MWRA to begin testing daily, officials said.

Like other coronavirus metrics in the state, the waste water tests paint a picture of a state that appeared to wrestle the virus under control this summer but has seen it make a gradual comeback that accelerated in the past two weeks.

Hoping to stem a rising tide of infections and hospitalizations, Governor Charlie Baker on Monday pumped the brakes on the state’s reopening. He imposed tighter restrictions that included requiring most businesses to close by 9:30 p.m. and reducing limits on the size of gatherings. The governor also modified his mask order to require people to wear masks in public, no matter how distant they are from other people.

In related news, a University of Massachusetts model suggested the state’s coronavirus death tally will rise to around 10,662 by Nov. 28.

Researchers noted that the numbers could range between 10,488 and 10,877.

The model numbers reflect both confirmed and probable coronavirus deaths. The state as of Wednesday had tallied 10,062 confirmed and probable deaths, including 9,836 deaths in confirmed cases.

Reich’s lab collects various models and develops a combined forecast that is intended to reflect their collective wisdom.

The lab only creates the forecast for a four-week window ahead because researchers believe forecasts aren’t reliable enough after that.

Associate professor Nicholas Reich’s UMass lab posts its national- and state-level data every week at the Reich Lab COVID-19 Forecast Hub. The lab, already an Influenza Forecasting Center of Excellence, collaborates with the US Centers for Disease Control and Prevention on coronavirus predictions. The lab feeds the data it has collected and its ensemble forecast to the federal agency, which posts the data on its own website.

Researchers from Google who have collaborated with Harvard on a model that looks only two weeks ahead predicted 10,221 coronavirus deaths in Massachusetts by Nov. 16. The UMass model was less optimistic, predicting around 10,322 deaths by Nov. 14.

The UMass model also predicts that the total number of coronavirus deaths in the United States will reach around 257,000 by Nov. 21.