An encouraging downward trend in coronavirus levels in Eastern Massachusetts waste water was interrupted by two upticks late last week.
The seven-day average virus level edged up Thursday and then down Friday in the northern section of the Massachusetts Water Resources Authority system, while the level in the southern section was flat Thursday before edging up Friday.
Officials say waste water virus data can be an important early warning signal, detecting COVID-19 infections before people get tested and the tests are officially reported. As more people are using rapid at-home tests, whose results are usually not reported to state public health officials, waste water testing has become a key indicator of the virus’s prevalence.
Waste water test results for more recent days weren’t expected to be released until Wednesday.
The recent declines in the waste water numbers come as the state’s COVID-19 case numbers have also been moving down.
Pandemic models have suggested that COVID-19 infections in Massachusetts, which had been rising for weeks, would crest before summer. Experts said they thought that would happen for a variety of reasons, including the immune protection people had gotten from vaccinations and previous infections, and the arrival of warmer weather.
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 water is tested for traces of the deadly virus. The MWRA reports numbers for both the southern and northern regions of its system. 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 was 944 RNA copies/mL as of Friday. The number had gone as high as 1,273 on May 17. In the southern section, the seven-day average was 892 RNA copies/mL on Friday. The number had gone as high as 1,332 on May 17.
After the devastating Omicron surge early this year, levels plummeted. They bottomed out in early March before beginning to rise slowly again as experts warned of the looming threat of Omicron subvariants such as BA.2 and BA.2.12.1.
Dr. Anthony Fauci, President Biden’s chief medical adviser on the pandemic, said Sunday on New York City’s PIX 11 that he didn’t think the coronavirus could be eliminated, but he hoped it could be brought under control.
“We certainly are not there yet,” he said, but officials are hoping to get the virus down to “a level low enough that it doesn’t disrupt us to the extent that it has over the past couple of years.”
“I believe that we’re going to be dealing with this virus on a chronic basis,” he said.
He said there was “a reasonably good chance that we will have the same sort of situation that we have with influenza,” where every year people are asked to get a shot to keep their protection up.
Material from prior Globe stories was used in this report.
Martin Finucane can be reached at firstname.lastname@example.org.