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After a brief climb, levels of coronavirus waver in Eastern Mass. waste water

The water flowing into the sewage treatment plant at Deer Island on Boston Harbor is tested for traces of coronavirus.David L. Ryan/Globe Staff

The levels of coronavirus detected in Eastern Massachusetts waste water are wavering after a brief steep climb, according to the latest data from the Massachusetts Water Resources Authority.

The levels of virus detected in both sections of the MWRA system peaked last week and have been fluctuating up and down since then, with the northern section ticking up as of Monday and the southern section ticking down.

The numbers remain far below the stratospheric highs that were reached early this year at the beginning of the Omicron variant wave.

Officials say waste water data from the MWRA can be an early warning signal, detecting COVID-19 infections before people get tested and the tests are officially reported.


The numbers have become even more crucial as more people are using rapid, at-home tests that don’t get reported and reflected in official case counts.

Waste water from 43 communities, including Boston, converges at the MWRA’s Deer Island plant on Boston Harbor for treatment before being piped miles into the ocean. The sewage is tested for traces of the deadly virus. The MWRA reports numbers for both the northern and southern sections of its system. The testing determines the number of SARS-CoV-2 RNA copies per milliliter of waste water.

The seven-day average count for the northern section reached 1,016 copies/mL of the virus on Sept. 26. It then fluctuated at lower levels, eventually ticking up to 874 copies/mL on Monday.

The count for the southern section rose as high as 1,185 copies/mL on Saturday, but saw two days of downticks that brought it to 1,041 on Monday.

Experts have said they expect COVID-19 to make a comeback this fall and winter, but it likely won’t be as bad as the past two years because it will be blunted by the immunity people have built up from previous infections, vaccinations, and updated boosters. There’s a catch, however: A new variant could change the game significantly.


Hundreds of people still die each day nationally from the virus, including about eight a day in Massachusetts, according to figures released last Thursday on confirmed and probable deaths by the Massachusetts Department of Public Health. But those and other coronavirus metrics have dropped from the terrifying peaks early this year.

“Right now, it looks like we’re going in the right direction. However, we are entering into the winter months, where no matter what the respiratory disease is, there’s always a risk of an uptick in respiratory diseases,” Dr. Anthony Fauci, the nation’s top infectious disease expert, said Tuesday at a USC Annenberg Center for Health Journalism event.

Fauci noted the “creeping up” of new variants and said, “Although we can feel good that we’re going in the right direction, we can’t let our guard down.”

Officials and experts have urged people to get vaccinated and to get updated boosters to protect themselves and others in the coming months. The US Centers for Disease Control and Prevention also recommends a variety of other precautions, such as increasing ventilation, avoiding people who have COVID-19, and isolating if you have a suspected or confirmed case.

In counties where the COVID-19 level is high, the CDC recommends masking in indoor public spaces. Berkshire County is currently in that category.

Material from previous Globe stories was used in this report.


Martin Finucane can be reached at martin.finucane@globe.com.