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The level of coronavirus detected in Mass. waste water just shot up

A view of the Deer Island waste water treatment plant in Boston.David L. Ryan/Globe Staff

After fluctuating for several months, the levels of coronavirus detected in Eastern Massachusetts waste water began rising in recent days, according to data.

Officials say waste water data from the Massachusetts Water Resources Authority can be an early warning signal, detecting changes in the number of COVID-19 infections before people get tested and the results officially reported.

“The waste water data has been really good at predicting a coming wave of COVID and, given that we’ve just come out of the [Thanksgiving] holiday, it’s very unsurprising that we would see an increase in cases,” said Matthew Fox, a professor of epidemiology and global health at the Boston University School of Public Health.


COVID-19 cases have risen every fall and winter since the start of the pandemic, but never as dramatically as last year, when the arrival of the Omicron variant triggered unprecedented rates of illness and hospitalizations. It’s too early to tell whether the new waste water numbers presage a significant, prolonged spike, experts said.

The MWRA reports numbers for both the southern and northern sections of its system. The southern section includes parts of Newton and Brookline as well as Framingham, Ashland, and Stoughton. The northern section stretches north from Boston to Wilmington.

The testing determines the number of SARS-CoV-2 RNA copies per milliliter of waste water.

In the northern MWRA section, the seven-day average count of the virus reached a measure of 759 on Tuesday. The number had been as high as 8,644 last January and as low as around 100 in March.

In the southern section, the seven-day average count was higher on Tuesday — 937. The numbers for that region had been as high as 11,446 last January, but fell below 100 in March. The last time numbers for both the southern and northern sections were this high was in late October.


“We’ve got a pretty highly vaccinated population so, while I do expect to see an increase in cases, the hope remains that we will not see a very sharp rise in hospitalizations and deaths,” Fox said.

However, the rates of Boston residents who have received Omicron-specific bivalent boosters has remained low — a cause for concern among many public health experts. There are also clear racial disparities in who is getting boosted: Only 7 percent of Hispanic residents and 9 percent of Black residents have received the bivalent booster, compared to 11 percent of AAPI residents and 13 percent of white residents, according to the Boston Public Health Commission.

The BPHC is working to close that gap and has opened free vaccination and testing sites across the city, focusing on communities that have been disproportionately impacted by the pandemic including Roxbury and Dorchester.

“Most Americans have not gotten booster shots yet, and even people who have are probably well beyond the point where they have a lot of protection from whatever their last dose was,” said Andrew Lover, assistant professor of Public Health at the University of Massachusetts Amherst.

This lack of coverage may mean that new variants of the coronavirus, such as BQ.1 and XBB, which are on the rise around the country, may impact the US more severely than countries such as Germany and France, where those variants have caused only small upticks in severe cases and hospitalizations relative to previous waves, he said.


Over the past two weeks, COVID-19 cases in Boston have increased by 14 percent while hospitalizations increased by 24 percent, according to the Boston Public Health Commission. That’s in addition to an outbreak reported Wednesday at the Holyoke Soldiers’ Home in Holyoke, where, as of Friday, 11 long term care veteran residents and 20 staff had tested positive for the virus.

The state’s Executive Office of Health and Human Services said in a statement that residents had reported mild symptoms and had been isolated and treated for COVID. In spring 2020, the Home was the site of one of the nation’s most notorious and deadly outbreaks of the virus, killing 84 veterans.

Across Massachusetts, confirmed and probable cases were down from a recent peak in late September and remain lower than they were this time last year, according to data from the state health department. Hospitalizations are also lower now than last year, though they have risen in recent days.

Julia Raifman, assistant professor of Public Health at Boston University, encouraged policy leaders to consider reinstating measures that can help reduce the spread of COVID-19 and other respiratory illness, such as implementing mask policies and expanding testing.

“We need leadership to create in a virtuous cycle of caring about one another and protecting people who are disproportionately harmed by COVID and the other respiratory viruses,” she said. “That takes policy leadership, we see that nothing an individual can do is nearly as powerful as what a policymaker can do for reducing transmission.”


Zeina Mohammed can be reached at zeina.mohammed@globe.com. Follow her @_ZeinaMohammed.